Endangered and Threatened Wildlife; 12-Month Finding on Petitions To List the Northeastern Pacific Ocean Distinct Population Segment of White Shark as Threatened or Endangered Under the Endangered Species Act, 40104-40127 [2013-16039]

Agencies

• DEPARTMENT OF COMMERCE
• National Ocean and Atmospheric Administration

[Federal Register Volume 78, Number 128 (Wednesday, July 3, 2013)]
[Notices]
[Pages 40104-40127]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-16039]


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DEPARTMENT OF COMMERCE

National Ocean and Atmospheric Administration

[Docket No. 120807313-3560-02]
RIN 0648-XC154


Endangered and Threatened Wildlife; 12-Month Finding on Petitions 
To List the Northeastern Pacific Ocean Distinct Population Segment of 
White Shark as Threatened or Endangered Under the Endangered Species 
Act

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice of 12-month finding and availability of status review 
documents.

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SUMMARY: We, NMFS, announce a 12-month finding on two petitions to list 
the northeastern Pacific (NEP) population of white sharks

[[Page 40105]]

(Carcharodon carcharias) as threatened or endangered under the 
Endangered Species Act (ESA). We have completed a status review of the 
NEP white shark population in response to these petitions using the 
best available scientific and commercial data. Based on this review, we 
have determined that the NEP white shark population qualifies as a 
distinct population segment (DPS) under the ESA and does not warrant 
listing under the ESA. Based on the considerations described in this 
notice, we conclude that the NEP white shark DPS is neither in danger 
of extinction throughout all or a significant portion of its range nor 
likely to become so within the foreseeable future.

DATES: This finding was made on July 3, 2013.

ADDRESSES: The status review documents for the NEP white shark 
population are available by submitting a request to the Assistant 
Regional Administrator, Protected Resources Division, Southwest 
Regional Office, 501 W. Ocean Blvd., Suite 4200, Long Beach, CA 90802, 
Attention: White Shark 12-month Finding. The documents are also 
available electronically at: https://swr.nmfs.noaa.gov/.

FOR FURTHER INFORMATION CONTACT: Craig Wingert, NMFS, Southwest 
Regional Office, (562) 980-4021 or Marta Nammack, NMFS, Office of 
Protected Resources, (301) 427-8469.

SUPPLEMENTARY INFORMATION: 

Background

    On June 25, 2012, we received a petition from WildEarth Guardians 
to list the NEP population of the white shark as threatened or 
endangered and to designate critical habitat for the population under 
the ESA. On August 13, 2012, we received a second petition, filed 
jointly by Oceana, Center for Biological Diversity and Shark Stewards, 
to list the NEP white shark population under the ESA and to designate 
critical habitat for the population. Both petitions presented much of 
the same or related factual information on the biology and ecology of 
white sharks, and raised several identical or similar issues related to 
potential factors affecting the NEP population of this species. On 
September 28, 2012, we published a positive 90-day finding (77 FR 
59582) announcing that both petitions presented substantial scientific 
or commercial information indicating that the petitioned action may be 
warranted. In our 90-day finding, we also announced the initiation of a 
status review of the NEP white shark population and requested 
information to inform our decision on whether this population 
constituted a DPS and warrants listing as threatened or endangered 
under the ESA.

ESA Statutory Provisions

    The ESA defines ``species'' to include any subspecies or DPS of any 
vertebrate species which interbreeds when mature (16 U.S.C. 1532(16)). 
The U.S. Fish and Wildlife Service (FWS) and NMFS have adopted a joint 
policy describing what constitutes a DPS under the ESA (61 FR 4722). 
The joint DPS policy identifies two criteria for making a determination 
that a population is a DPS: (1) The population must be discrete in 
relation to other conspecific populations; and (2) the population must 
be significant to the taxon to which it belongs.
    A population segment of a vertebrate species may be considered 
discrete if it satisfies either one of the following conditions: (1) It 
is markedly separated from other populations of the same taxon as a 
consequence of physical, physiological, ecological, or behavioral 
factors. Quantitative measures of genetic or morphological 
discontinuity may provide evidence of this separation; or (2) it is 
delimited by international governmental boundaries within which 
differences in control of exploitation, management of habitat, 
conservation status, or regulatory mechanisms exist that are 
significant in light of section 4(a)(1)(D) of the ESA. If a population 
segment is found to be discrete under one or both of the above 
conditions, its biological and ecological significance to the taxon to 
which it belongs is evaluated. Factors that can be considered in 
evaluating significance may include, but are not limited to: (1) 
Persistence of the discrete population segment in an ecological setting 
unusual or unique for the taxon; (2) evidence that the loss of the 
discrete population segment would result in a significant gap in the 
range of a taxon; (3) evidence that the discrete population segment 
represents the only surviving natural occurrence of a taxon that may be 
more abundant elsewhere as an introduced population outside its 
historic range; and (4) evidence that the discrete population segment 
differs markedly from other populations of the species in its genetic 
characteristics.
    Section 3 of the ESA defines an endangered species as ``any species 
which is in danger of extinction throughout all or a significant 
portion of its range'' and a threatened species as one ``which is 
likely to become an endangered species within the foreseeable future 
throughout all or a significant portion of its range.'' Thus, we 
interpret an ``endangered species'' to be one that is presently in 
danger of extinction. A ``threatened species,'' on the other hand, is 
not presently in danger of extinction, but is likely to become so in 
the foreseeable future (that is, at a later time). In other words, the 
primary statutory difference between a threatened and endangered 
species is the timing of when a species may be in danger of extinction, 
either presently (endangered) or in the foreseeable future 
(threatened). The ESA requires us to determine whether a species is 
endangered or threatened throughout all or a significant portion of its 
range because of any of the following five factors: (1) The present or 
threatened destruction, modification, or curtailment of its habitat or 
range; (2) overutilization for commercial, recreational, scientific, or 
educational purposes; (3) disease or predation; (4) the inadequacy of 
existing regulatory mechanisms; or (5) other natural or manmade factors 
affecting its continued existence.
    The ESA does not define the term ``significant portion of its 
range'' in the definitions for threatened and endangered species. NMFS 
and U.S. Fish and Wildlife Service (FWS; together the Services) have 
proposed a ``Draft Policy on Interpretation of the Phrase `Significant 
Portion of Its Range' in the Endangered Species Act's Definitions of 
`Endangered Species' and `Threatened Species' '' (76 FR 76987; December 
9, 2011), which is consistent with our past practice as well as our 
understanding of the statutory framework and language related to this 
term. While the Draft Policy remains in draft form, the Services are to 
consider the interpretations and principles contained in the Draft 
Policy as non-binding guidance in making individual listing 
determinations, while taking into account the unique circumstances of 
the species under consideration. The Draft Policy provides that: (1) If 
a species is found to be endangered or threatened in only a significant 
portion of its range, the entire species is listed as endangered or 
threatened, respectively, and the Act's protections apply across the 
species' entire range; (2) a portion of the range of a species is 
``significant'' if its contribution to the viability of the species is 
so important that, without that portion, the species would be in danger 
of extinction; (3) the range of a species is considered to be the 
general geographical area within which that species can be found at the 
time FWS or NMFS makes any particular status determination; and (4) if 
the species is not endangered or threatened

[[Page 40106]]

throughout all of its range, but it is endangered or threatened within 
a significant portion of its range, and the population in that 
significant portion is a valid DPS, we will list the DPS rather than 
the entire taxonomic species or subspecies.
    Section 4(b)(1)(A) of the ESA requires us to make listing 
determinations based solely on the best scientific and commercial data 
available after conducting a review of the status of the species (or 
DPS) and after taking into account efforts being made to conserve the 
species. In evaluating the efficacy of conservation efforts we rely on 
the Services' joint ``Policy for Evaluating of Conservation Efforts'' 
(``PECE''; 68 FR 15100; March 28, 2003). The PECE provides guidance to 
the Services on how to consider conservation efforts that have not been 
implemented, or have been implemented but not yet demonstrated to be 
effective.

Status Review and Biological Review Team

    As part of our comprehensive status review of the NEP white shark 
population, we formed a biological review team (BRT) comprised of 
Federal scientists from NMFS' Southwest Fisheries Science Center 
(SWFSC) having scientific expertise in shark biology and ecology, 
genetics, population estimation and modeling, fisheries management and 
conservation biology. We asked the BRT to compile and review the best 
available scientific and commercial information, and then to: (1) 
determine whether the NEP white shark population satisfied the criteria 
for being a DPS under the joint DPS policy; and (2) evaluate the 
extinction risk of the population, taking into account both threats to 
the population and its biological status.
    In conducting its review, the BRT considered a wide range of 
scientific information from the literature, unpublished documents, 
personal communications with researchers working on white sharks in the 
NEP and relevant technical information submitted to NMFS. The BRT 
recognized that there is considerable uncertainty regarding many 
aspects of white shark biology, abundance, trends in abundance and 
threats in the NEP. To address this uncertainty, the BRT explicitly 
defined issues that were uncertain and used a structured expert 
decision making (SEDM) approach to evaluate the plausibility of 
different scenarios after taking into account the best available data 
on the species, including information on white sharks from other 
geographic areas where necessary. The BRT prepared a report containing 
information on the biology, ecology and habitat use of white sharks in 
the NEP; information on whether the population constitutes a DPS under 
the ESA; and its assessment of the population's risk of extinction 
based on the best available information (Dewar et al., 2013). The BRT 
report was subjected to independent peer review as required by the 
Office of Management and Budget Final Information Quality Bulletin for 
Peer Review (M-05-03; December 16, 2004).

NEP White Shark Life History, Ecology, Distribution and Population 
Structure

    White sharks in the NEP belong to the species Carcharodon 
carcharias. The white shark is a circumglobal species that lives in 
coastal regions as well as the open ocean (Compagno, 2001) and is most 
frequently observed in inshore temperate continental waters of the 
Western North Atlantic, Mediterranean Sea, southern Africa, southern 
and Western Australia, and the NEP. Young-of-the-year (in their first 
year of life, YOY) and juvenile white sharks in the NEP are thought to 
prefer shallow coastal waters, primarily in the southern California 
Bight (SCB) and the west coast of Baja California (Dewar et al., 2001, 
Weng et al., 2007b). Adult and subadult white sharks in the NEP are 
most commonly observed near pinniped rookeries, but also range far from 
shore, spending protracted periods in pelagic habitats (Klimley, 1985; 
Bonfil et al., 1994; Domeier and Nasby-Lucas, 2007; Jorgensen et al., 
2010).

Growth and Reproduction

    Life history information related to growth and reproduction is 
relatively limited for the NEP white shark population, and therefore 
the BRT compiled the best available information for the species 
throughout its global range to characterize these life history 
parameters (Dewar et al., 2013). YOY white sharks range from 1.2 to 
1.75 m in total length (TL) (Francis, 1996). Juvenile white sharks 
range from 1.75 to 3.0 m TL and subadult white sharks range from 3.0 m 
TL up to the sizes at which males, as inferred from total length (3.6 
to 3.8 m TL) and calcification of their claspers, and females (4.5 to 
5.0 m TL) mature (Cailliet et al., 1985; Francis, 1996; Pratt, 1996; 
Winter and Cliff, 1999; Malcolm et al., 2001).
    A number of studies have used vertebral bands to construct von 
Bertalanffy growth curves for white sharks (Cailliet et al. 1985; 
Wintner and Cliff 1999; Malcolm et al,. 2001). These curves demonstrate 
that the growth of white sharks in the NEP (Cailliet et al, 1985) is 
similar to that for white sharks found off South Africa and Australia 
(Wintner and Cliff, 1999 and Malcolm et al., 2001, respectively). 
Francis (1996) summarized data for pregnant female white sharks from 
around the globe and reported that size at maturity ranged from 4.5-5.0 
m TL, which is similar to that reported by others (Malcolm et al., 
2001; Domeier and Nasby-Lucas, 2013). Length of gestation is uncertain, 
but is thought to be longer than a year and is estimated to be 18 
months (Francis 1996; Mollet et al., 2000; Domeier and Nasby-Lucas, 
2013). Consistent with the long gestation period, the frequency of 
pupping has been suggested to range between 2-3 years. The most 
quantitative information on pupping frequency comes from a photo 
identification (ID) study conducted at Guadalupe Island, Mexico, which 
estimated that females pup every 2.2 years (Nasby-Lucas and Domeier, 
2012). Mollet et al. (2000) reported that the average litter size of 
female white sharks was 8.9 pups.

Foraging Ecology

    Information on white shark foraging ecology comes from stomach 
content analysis and visual observations of larger shark feeding events 
(Klimley, 1985; Compagno et al., 1997; Skomal et al., 2012). Stomach 
contents of YOY and juvenile white sharks off southern California were 
found to include a range of bony fishes, cartilaginous fishes and 
crustaceans (Klimley, 1985). As white sharks reach a larger size (i.e., 
about 3 m TL), their diet expands to include marine mammals (Klimley, 
1985). The most important prey items include pinnipeds (i.e., seals, 
sea lions, and elephant seals) and fishes (including other sharks and 
rays) while less common prey items include marine reptiles (mostly sea 
turtles), larger cephalopods, gastropods, and crustaceans. White sharks 
have also been observed to scavenge large and small cetaceans (Compagno 
et al., 1997).

Distribution and Habitat Use

    Klimley (1985) found that YOY white sharks were caught south of 
Point Conception, California, whereas juveniles were caught both north 
and south of Point Conception. Based on this information, Klimley 
(1985) hypothesized that the SCB was a nursery area for white sharks. A 
more recent analysis of fishery interactions with white sharks in 
Southern California by Lowe et al. (2012) supports the notion that the 
SCB is a nursery area. These studies as well as those by Domeier (2012) 
indicate YOY first appear in incidental catch records

[[Page 40107]]

in April and peak in abundance in August. Both YOY and juvenile white 
sharks are caught predominantly in near-shore waters less than 50m in 
depth (Klimley, 1985; Lowe et al., 2012). YOY and juvenile white sharks 
have also been incidentally caught off the coast of Baja California in 
near-shore habitats (Santana-Morales et al., 2012), and juveniles have 
been incidentally caught in the Sea of Cortez (Galv[aacute]n-
Maga[ntilde]a et al., 2010).
    Recent tagging studies indicate that YOY white sharks remain 
between Point Conception and Sebasti[aacute]n Vizca[iacute]no Bay in 
Baja California (Dewar et al., 2004; Weng et al., 2007b; Weng et al,. 
2012). Weng et al. (2007b) also reported that YOY white sharks 
exhibited seasonal movements between California coastal waters in the 
summer and the coastal waters of northern Baja California in the fall, 
but this was based on very limited data. Weng et al. (2007b) tagged a 
total of 4 YOY and the tags only recorded data for 1-2 months before 
falling off. Two of the tagged individuals lost their tags in 
California in August and September and the other two individuals lost 
their tags in the fall in Baja California. Although there is evidence 
of seasonal movement, it is uncertain what portion of the YOY 
population moves to Mexico and whether or not they return to the SCB. 
Additional and longer tag deployments on YOY white sharks may reveal 
more extensive movements within the nursery area. Weng et al. (2012) 
also released 5 tagged YOY following a period of captivity at Monterey 
Bay Aquarium, some of which did not go to Mexico while some were 
tracked moving to Cabo San Lucas and into the Gulf of California.
    Klimley (1985) reported that sub-adult and adult white sharks were 
caught predominantly north of Point Conception with the largest 
concentration of sharks found off Central California near pinniped 
rookeries from Tomales Bay to Monterey Bay. The majority of attacks on 
humans and pinnipeds also occurred within these same areas, as well as 
in river mouths and harbors (McCosker and Lea, 1996). Klimley (1985) 
found that more females were caught south of Point Conception and 
hypothesized that females migrated south to give birth, suggesting that 
the area south of Point Conception is a nursery area.
    Klimley (1985) reported that white sharks occurred as far north as 
the southern end of Queen Charlotte Island off British Columbia. Martin 
(2005) examined available records of subadult and adult white shark 
sightings, captures, and strandings from 1961-2004 in British Columbia 
and Alaska and found they were most frequently present in the summer 
and fall months, that El Nino events did not impact the frequency of 
sightings or captures, and that there was no discernable trend in the 
species' presence over the years examined. The southern extent of the 
white shark range in the NEP appears to be Mexico. Adult and subadult 
white sharks have been documented by sightings and in incidental 
fishery catches within the Sea of Cortez (Galv[aacute]n-Maga[ntilde]a 
et al., 2010; Castro, 2012), with adults being most common from 
December to May and less common from June to October. Beginning in the 
late 1990s, subadult and adult white sharks were observed in increasing 
numbers at Guadalupe Island offshore from the Pacific coast of Baja 
California and by the early 2000s their presence was sufficiently 
predictable to support a commercial cage diving industry in the fall 
months. The western extent of the white shark's range in the NEP 
appears to be the Hawaiian Islands. White shark teeth have been found 
among artifacts in the Hawaiian Islands suggesting their historical 
presence in the area, but the species is rarely caught or observed 
there (Dewar et al., 2013). From 1926 to 2011 there were 14 confirmed 
observations of subadult or adult white sharks in the vicinity of the 
Hawaiian Islands (Taylor, 1985; Weng and Honebrink, 2013). No YOY or 
juvenile white sharks have been captured in the Hawaiian Islands, 
suggesting it is unlikely to be a nursery area. Electronic tagging 
studies also indicate that some white sharks migrate offshore from the 
aggregation sites in central California and Guadalupe Island to waters 
near the Hawaiian Islands (Domeier and Nasby-Lucas, 2008; Jorgensen et 
al., 2010).
    The majority of adult white shark activity in the NEP is observed 
at coastal sites and islands that serve as pinniped rookeries (Dewar et 
al., 2013). The Southeast Farallon Islands off central California serve 
as a rookery for a number of different pinniped species (northern 
elephant seals, California sea lions, northern fur seals, Steller sea 
lions and harbor seals) and have been one of the most predictable sites 
for observing white sharks in the NEP. Other sites where white sharks 
have been predictably observed in central California include Tomales 
Point, Point Reyes and A[ntilde]o Nuevo Island. Similarly, Guadalupe 
Island offshore Baja California in Mexico has recently become an 
important aggregation site for white sharks. The consistent presence of 
white sharks at these aggregation sites has provided the opportunity 
for researchers to conduct photo-ID studies because of the unique 
identifying characteristics exhibited by white sharks and their 
predictable occurrence over time.
    Anderson et al. (1996) initiated a photo-ID study of white sharks 
at Southeast Farallon Island in 1987, which was subsequently expanded 
to include coastal areas near Tomales Point in 1988. The study found 
that the same individuals returned to these areas repeatedly, with 
males typically returning on an annual basis and females on a semi-
annual basis. Males were sighted nearly twice as often as females, 
though this ratio is most likely biased because it is easier to confirm 
the presence of male claspers rather than their absence. One specific 
male white shark has been found to occur at Southeast Farallon Island 
over a period of 22 years (Anderson et al., 2010). Based on photo-ID 
studies conducted at Guadalupe Island, Domeier and Nasby-Lucas (2007) 
and Nasby-Lucas and Domeier (2012) found that adult male and female 
white sharks exhibit patterns of occurrence similar to those found for 
white sharks in central California, with males returning annually and 
mature females typically returning on a semi-annual basis. As was the 
case in central California, they also observed more males than females; 
however, the sex ratio shifted during fall months as males and females 
arrived at different times.
    Studies using pop-up satellite archival tags (PSAT) have shown that 
sharks tagged at both Southeast Farallon Island and Guadalupe Island 
undertake long range migrations to an offshore focal area (OFA) in the 
NEP located approximately midway between the west coast of North 
America and the Hawaiian Islands and then return to the aggregation 
sites where they were originally tagged in the fall (Boustany et al., 
2005; Weng et al., 2007a; Domeier and Nasby-Lucas, 2008; Jorgensen et 
al., 2010). A relatively small number of white sharks tagged at these 
two aggregation sites move as far west as the Hawaiian Islands (Domeier 
and Nasby-Lucas, 2008; Jorgensen et al., 2010). This OFA has been 
termed either the white shark caf[eacute] or the Shared Offshore 
Foraging Area by different research groups (Domeier, 2012; Jorgensen et 
al., 2012).
    Researchers have also used smart position and temperature (SPOT) 
tags to document white shark movements from both the central California 
and Guadalupe Island aggregation sites. SPOT tag data for white sharks 
from Guadalupe Island confirm that females typically do not return to 
the

[[Page 40108]]

aggregation site on a yearly cycle and instead remain offshore for 
about 15 months, which is presumed to be associated with their 18-month 
gestation cycle (Domeier and Nasby-Lucas, 2012). After spending 15 
months offshore, 4 tagged females returned to coastal waters between 
April and August when YOY are seasonally present, suggesting that they 
may have migrated there to give birth. Two of the females were tracked 
into the Sea of Cortez in June and July when white sharks are rare 
according to information presented in Galv[aacute]n-Maga[ntilde]a et 
al. (2010), and two were tracked to the Pacific coast of Baja 
California near Sebasti[aacute]n Vizca[iacute]no Bay (Domeier and 
Nasby-Lucas, 2013). All four females then returned to the Guadalupe 
Island aggregation site between late September and early October after 
the normal return time for male white sharks.
    Analysis of both types of satellite tag data suggests that there is 
sexual segregation of white sharks in the OFA, with males from the 
aggregation sites in central California and at Guadalupe Island using a 
smaller and more predictable offshore area and females roaming over a 
larger and less predictable area (Jorgensen et al., 2009; Domeier and 
Nasby-Lucas, 2012). The habitat function of the OFA and the coastal 
aggregation sites is a source of disagreement between different 
researchers and centers around whether the OFA or the coastal 
aggregation sites are used for mating. Jorgensen et al. (2010 and 2012) 
argue the OFA is a mating area and Domeier (2011) and Domeier and 
Nasby-Lucas (2013) argue the coastal aggregation sites are used for 
mating.
    To complement data obtained from the PSAT and SPOT tagging studies, 
researchers in central California have used an acoustic array to 
document the movements of white sharks in and around the known sites 
where white sharks aggregate. Acoustic tracking data for white sharks 
tagged in central California showed that upon their return to the coast 
from offshore, tagged white sharks were detected by receivers at a 
number of central California locations. Tracking data during the 
coastal aggregation period (August through February) suggest that white 
sharks preferred a limited number of key hotspots and that some 
individual sharks showed a distinct preference for specific sites 
(Dewar et al., 2013).
    Despite their long-range offshore movements, satellite tagged white 
sharks from central California have not been tracked moving to 
Guadalupe Island or vice versa. However, a female white shark that was 
SPOT tagged at Guadalupe Island was found to migrate offshore and 
return back to the coast to an area just off Point Conception (M. 
Domeier, MCSI, personal communication) and a small number of 
acoustically tagged white sharks have been found to move between the 
two areas (Jorgensen et al., 2012; S. Jorgensen, Monterey Bay Aquarium, 
personal communication as cited in Dewar et al., 2013).

Genetic Information on White Shark Population Structure and Population 
Size

    Genetic data provide valuable insight into white shark population 
structure and connectivity between populations in different ocean 
basins, as well as historical abundance. A comparison of mitochondrial 
DNA (mtDNA) samples taken from white shark populations in central 
California, South Africa and Australia/New Zealand showed strong 
clustering of samples from California with those from Australia/New 
Zealand. The analysis also provided evidence that the NEP white shark 
population forms a unique monophyletic clade (i.e., a group evolved 
from a single common ancestral form) that was derived relatively 
recently from the Australia/New Zealand population. It has been 
hypothesized that the NEP white shark population was founded by 
Australia/New Zealand migrants during the Late Pleistocene (~150,000 
years ago) and that subsequent strong homing behavior and reproductive 
site fidelity has maintained the separation between the two populations 
(Jorgensen et al., 2009).
    The pattern of genetic diversity observed in white shark samples 
suggests the population has undergone a rapid demographic expansion 
since it colonized the NEP (Dewar et al., 2013). Although the overall 
number of genetic samples is relatively low for all geographic areas, 
observations that the NEP white shark population lineage is 
monophyletic and that no shared haplotypes have been observed between 
samples from different regions strongly indicates the NEP population is 
genetically distinct (Dewar et al., 2013). However, because only mtDNA 
data are presently available and this genetic material is inherited 
maternally, the available genetic information only reflects patterns of 
female gene flow and behavior. Future use of nuclear DNA markers is 
needed to determine whether male mediated gene flow follows a similar 
pattern (Dewar et al., 2013).
    The number of haplotypes (i.e., specific genetic sequences that are 
inherited from the maternal parent's haploid mitochondrial genome) 
expected in a given population depends, among other things, on its 
effective population size (Dewar et al., 2013). For populations that 
are naturally low in abundance, the number of haplotypes is expected to 
be low and normally there would be no truly rare haplotypes (defined by 
the BRT as haplotypes found at frequencies equal to or less than 5 
percent). In shark and cetacean populations with a low number of 
haplotypes (e.g., 1-5 haplotypes), the abundance of females in the 
population is in the low hundreds of individuals or less (see Table 2.2 
in Dewar et al., 2013). In contrast, higher haplotype diversity is 
consistent with a population that is currently large or was larger in 
the past, but has suffered a significant decline in the last few 
generations (Hoelzel et al., 1993, as cited in Dewar et al., 2013). 
Based on an evaluation of the available genetic information on white 
sharks from central California (see Jorgensen et al., 2010), the BRT 
found that the number of haplotypes and the number of low frequency 
haplotypes in the NEP white shark population were relatively high 
(Dewar et al., 2013). The BRT compiled information on haplotype 
diversity and population abundance for a range of marine mammal and 
shark species that were long-lived, slow reproducers and not 
characterized by strong social structure, and compared this information 
to the haplotype numbers and diversity observed for white sharks in the 
NEP (see Table 2.2 in Dewar et al., 2013). Based on this comparison, 
the haplotypic diversity of the NEP white shark population is 
comparable to that of other species where the abundance of females is 
in the high hundreds to low thousands of individuals. Given the 
relationship between haplotype diversity and female abundance and the 
observed haplotype diversity for white sharks in the NEP, the BRT 
suggested that the NEP white shark population is either much more 
abundant than indicated by recent estimates based on photo-ID data from 
central California and Guadalupe Island (Chapple et al., 2011; Sosa-
Nishizaki et al., 2012) or that the population was historically larger 
and has declined substantially in the last few generations.
    The BRT addressed the potential for a substantial decline in the 
NEP white shark population over the past two generations (i.e., 
approximately 40 years) by conducting a Monte Carlo modeling exercise 
that imposed a relatively high level of fisheries-related mortality on 
a white shark population to determine if it was feasible to induce a 90 
percent population decline over two generations (see Appendix B in 
Dewar et al., 2013). The modeled scenarios

[[Page 40109]]

assumed starting white shark populations consisting of only 500 and 
1,000 adult females and imposed fishery-mortality rates that were high 
in comparison to current estimated rates. Under these scenarios, 
fisheries mortality caused population declines, but the modeling 
results indicate that present day abundance of female white sharks 
would still number several hundred individuals. Based on this analysis, 
the BRT determined that: (1) The NEP white shark population is not 
likely to have undergone a dramatic decline in abundance over the past 
two generations (40 years); and (2) the population's haplotypic 
diversity reflects a present day adult female population that is much 
larger than suggested by current population estimates (see Appendix B 
in Dewar et al., 2013).

NEP White Shark DPS Determination

    The BRT evaluated the best available information for the NEP white 
shark population to determine whether it meets the discreteness and 
significance criteria in the joint DPS policy (see ESA Statutory 
Provisions section). All relevant information related to the 
discreteness and significance criteria was thoroughly discussed by the 
BRT and arguments were developed for and against each factor that was 
considered. The BRT used a SEDM approach for expressing uncertainty 
about how different type of information (e.g., behavior, genetics, 
etc.) related to the discreteness and significance criteria (Dewar et 
al., 2013).

Discreteness

    Based on a careful review of the best available information, the 
BRT concluded that the NEP white shark population is markedly separated 
from other populations of the same taxon as a consequence of behavioral 
characteristics (Dewar et al., 2013). Information supporting this 
conclusion includes: (1) The site fidelity exhibited by NEP white 
sharks from the two studied aggregation sites (i.e., central California 
and Guadalupe Island); (2) tagging information that shows movement of 
white sharks only within the NEP; and (3) the lack of shared mtDNA 
haplotypes between the NEP white shark population and white shark 
populations from other areas (e.g., Australia/New Zealand and South 
Africa) which suggests little movement of sharks or gene flow among 
these areas. All of the available tagging and photo-ID data from the 
two known aggregation sites in the NEP indicate that subadult and adult 
males and females exhibit consistent migration patterns with 
individuals moving between the aggregation sites and an offshore 
pelagic habitat located between the Hawaiian Islands and the North 
American mainland. Similarly, tagging studies of YOY and juvenile white 
sharks in the NEP also indicate that their movements are restricted to 
the coastal waters of North America. Results from genetic studies using 
mtDNA markers indicate that the NEP white shark population does not 
share any haplotypes with populations in other regions suggesting there 
is little to no gene flow between the NEP population and populations in 
other regions. The available mtDNA data are only indicative of female-
mediated gene flow, and therefore additional information is needed to 
confirm that males do not move from the NEP to other areas such as 
Australia or New Zealand. Accordingly, the BRT found that the available 
evidence strongly supports a finding that NEP white sharks are markedly 
separate from white shark populations in other regions based on a 
consideration of behavioral factors (Dewar et al., 2013).

Significance

    The BRT evaluated the available information relating to the 
possible significance of the NEP white shark population and focused on 
two factors: (1) Genetic differences between the NEP white shark 
population and other populations found in the Pacific and Atlantic 
Oceans; and (2) whether the loss of the NEP white shark population 
would create a significant gap in the species' global range. Based on a 
thorough evaluation of the available information, the BRT found that 
the NEP white shark population is significant to the global taxon based 
on both of these two factors (Dewar et al., 2013).
    The BRT evaluated the genetic differences between the NEP white 
shark population and populations found in other regions by comparing 
the results of mtDNA analysis of white shark samples from Central 
California (the NEP white shark population), Japan, Australia/New 
Zealand and South Africa. A comparison of these data revealed that the 
NEP white shark population does not share mtDNA haplotypes with 
populations from any other area, suggesting it represents a unique 
monophyletic clade. The level of mtDNA differentiation between 
populations suggests that less than one migrant per generation migrates 
between areas and that enough time has passed to allow white sharks to 
adapt to habitat conditions in the NEP. Although the mtDNA data provide 
information only about potential female movement and gene flow among 
regions, many of the individuals analyzed from the NEP white shark 
population were adult males with haplotypes indicating that they were 
of NEP origin and photographic histories showing that they were 
repeatedly observed at the aggregation sites in the NEP. The BRT 
identified some issues with the available genetic data (e.g., small 
sample sizes for most genetic studies, the use of only maternally 
inherited markers, etc.), but concluded based on a SEDM assessment that 
the data show marked genetic differences between the NEP white shark 
population and other white shark populations that were analyzed (Dewar 
et al., 2013).
    The BRT also evaluated the range of the NEP white shark population 
in comparison with the species' global distribution to assess whether 
the loss of the NEP population would constitute a significant gap in 
the species' range (Dewar et al., 2013). The BRT determined that the 
NEP white shark population occupies approximately half of the North 
Pacific Ocean and concluded that this area represents a significant 
part of the taxonomic species' global range. Based on these 
considerations, the BRT concluded that loss of the NEP white shark 
population would constitute a significant gap in the taxonomic species' 
global range (Dewar et al., 2013).

Conclusion

    Based on a consideration of the best available information, the BRT 
found that the NEP white shark population is: (1) Discrete to the 
global taxon because it is markedly separated from other white shark 
populations based on behavioral factors; and (2) significant to the 
global taxon based on evidence that the population differs markedly in 
its genetic characteristics from other populations and because loss of 
the population would result in a significant gap in the range of the 
global taxon. We concur with the BRT's findings, and therefore conclude 
that the NEP white shark population constitutes a DPS under the ESA.

Significant Portions of the NEP White Shark Population's Geographic 
Range

    As part of its status review, the BRT evaluated whether there were 
portions of the NEP white shark population's geographic range that 
could potentially constitute a significant portion of its range. 
Although several portions of the geographic range occupied by the NEP 
white shark population are biologically important (e.g., central 
California and Guadalupe Island aggregation sites, SCB

[[Page 40110]]

and northern Baja coastal nursery habitat, offshore pelagic habitat), 
the BRT focused on evaluating whether there were important threats to 
the population that were concentrated in specific areas that might 
constitute a significant portion of the range of the population. Based 
on its threats evaluation, the BRT concluded that fisheries bycatch is 
the main threat to the population and the largest known current threat 
is the bycatch of YOY and juvenile white sharks in gillnet fisheries 
that occur in the coastal waters of the SCB and northern Baja 
California (see Evaluation of Threats section). Within this geographic 
area, which is considered to be the nursery area for YOY and juvenile 
white sharks in the NEP, most documented fisheries bycatch occurs along 
the Baja California coast from the U.S.-Mexico border to 
Sebasti[aacute]n Vizca[iacute]no Bay, but there is also bycatch of YOY 
and juveniles in the SCB. Recent tagging studies (Weng et al., 2007b; 
Weng et al., 2012) have tracked some YOY white sharks moving from the 
SCB to coastal Mexican waters including Sebastian Vizcaino Bay and the 
Sea of Cortez, suggesting that the nursery habitat in the SCB is 
connected to the nursery habitat in northern Baja California. Because 
this nursery habitat is used by the entire NEP white shark population, 
the BRT concluded that fishery bycatch impacts in the nursery habitat 
affect the entire population rather than any specific population 
segment. Similarly, adult and subadult white sharks tagged at the known 
coastal aggregation sites in central California and at Guadalupe Island 
undertake seasonal offshore migrations and males and females use common 
areas in the NEP between the Hawaiian Islands and the coast of North 
America. While occupying this offshore habitat, adult and subadult 
white sharks from throughout the range of the NEP population are 
exposed to similar threats. Based on these considerations, the BRT 
determined that the most significant threats to the population affect 
the NEP population as a whole rather than any specific segments of the 
population. As a consequence, the BRT found, and we concur, that there 
are no identifiable portions of the NEP white shark population that 
constitute a significant portion of the population's range. 
Accordingly, the BRT's extinction risk assessment was based on the NEP 
white shark population throughout its entire range.

Assessment of NEP White Shark Extinction Risk

    The BRT considered a wide range of information in assessing the 
extinction risk of the NEP white shark population including: (1) 
Potential threats to the population; (2) direct and indirect 
information regarding trends in population abundance; (3) population 
abundance estimates and factors that bias abundance estimates; and (4) 
population modeling to assess the risks associated with fisheries 
bycatch on the population under a range of population levels. The 
following discussion summarizes information considered by the BRT, the 
results of its analyses, and its overall extinction risk conclusions 
(see Dewar et al., 2013).

Evaluation of Threats

    The BRT identified and compiled information on a range of potential 
threats to the NEP white shark population (Dewar et al., 2013). These 
included several fisheries (i.e., high seas driftnet fishery; coastal 
set net fisheries off of California; gillnet fisheries in Mexico and 
recreational fisheries off of California); depletion of white shark 
prey resources; potential small population effects; disease and 
predation; habitat degradation (i.e., environmental contamination) and 
climate change effects (i.e., ocean acidification and ocean warming). 
Following a review of this information, the BRT assessed the severity 
of each threat to the population and how certain each threat was likely 
to occur. In making this assessment, the BRT considered the current and 
foreseeable future risks of each threat to the population, and in some 
cases also assessed the historical risks of some threats where 
information was available to do so. The BRT also grouped individual 
threats into specific threat categories (e.g., habitat destruction, 
overutilization, etc.) which were then evaluated in terms of their 
overall risk (e.g., none, low, moderate and high) to the NEP white 
shark population. Where appropriate, we incorporated the BRT's analysis 
and findings about threats in our evaluation of the five factors that 
must be considered in accordance with section 4(a)(1) of the ESA. More 
detailed information regarding the threats assessment can be found in 
Dewar et al. (2013).
    In summary, the BRT found that threats associated with habitat 
degradation, disease and predation, and small population size effects 
are currently a low risk to the NEP white shark population and are 
likely to remain low in the foreseeable future. The BRT found that 
high-seas driftnet fisheries and coastal gillnet fisheries were a 
moderate threat to the population in the past, but that the magnitude 
of this threat has diminished substantially in recent years. However, 
the BRT found that white shark mortality associated with coastal 
gillnet fisheries off southern California and Baja California were of 
concern and considered this threat to be a moderate risk to the NEP 
white shark population now and in the foreseeable future. For several 
other threats (e.g., disease and global warming related effects), the 
BRT concluded that the available information to assess the threats for 
the population was limited, and therefore, it expressed a relatively 
high degree of uncertainty in its assessments of those threats. 
Overall, the BRT concluded that bycatch of white sharks in coastal 
gillnet fisheries was currently the main threat to the population and 
was likely to remain so in the foreseeable future.

Evaluation of Trend Information

    Trend information is considered highly informative in assessing a 
population's risk of extinction (Musick et al., 1999); therefore, the 
BRT summarized and evaluated direct and indirect information related to 
trends in the abundance of the NEP white shark population from a 
variety of different sources. These information sources included: (1) 
White shark catch and effort data for coastal gillnet fisheries in 
southern California; (2) white shark abundance estimates at Guadalupe 
Island; (3) white shark attack frequency on marine mammals; and (4) 
information regarding possible range expansion of the population.
    Population trends can be evaluated by examining trends in catch-
per-unit-effort (CPUE). For analysis of CPUE, the BRT used white shark 
catch data and effort data for the California set gillnet fishery, 
which has accounted for a large majority of the bycatch of white sharks 
in California waters since the early 1980s (Dewar et al., 2013). Across 
the entire time series of available logbook data (1981-2011), CPUE in 
this fishery appears to have declined from the early 1980s through the 
mid-1990s and generally increased since that time. The period of 
increasing CPUE since the mid-1990s also coincided with a steady 
decline in fishing effort as a result of changes in fishery 
regulations. The BRT was concerned that increasing CPUE during the 
2000s could be caused by increased reporting rates associated with the 
Monterey Bay Aquarium white shark scientific collection program, which 
beginning in 2002 incentivized fishermen to report their catches, but 
concluded that increased reporting did not fully account for the 
observed trend in CPUE (Dewar et al., 2013). The BRT was also concerned 
that the increase in CPUE during the 2000s could also have

[[Page 40111]]

been caused by an increase in the average soak time per set (i.e., the 
amount of time fishing nets are left in the water to fish before being 
retrieved) in recent years. The BRT used multiple linear regression 
analysis to examine the potential impact of soak time per set on CPUE 
over time for the period from 1994-2001 and found there was a 
significant increase in CPUE over that period and that soak time was 
not a significant contributing factor (Dewar et al., 2013).
    The white shark photo-ID study conducted at Guadalupe Island 
provided the BRT with an opportunity to examine trends in white shark 
abundance at that site over the period from 2001-2011. As discussed in 
Dewar et al. (2013), the BRT's re-analysis of photo-ID data for white 
sharks observed at Guadalupe Island allowed for the estimation of 
annual population abundance over this period. The time series of annual 
abundance estimates from this analysis showed there was an increasing 
trend in male abundance from 2001-2011, with the number of males 
approximately doubling, from about 40 males in 2001 to over 90 males in 
2011. Over the same time period, females increased in abundance for the 
first several years of the study, and then their abundance level 
stabilized after 2006. The BRT believed that abundance of females may 
have been underestimated in the years after 2007 because sampling 
effort decreased in those years for the months of November and December 
when females were still present at Guadalupe Island.
    Observations of white shark attacks on marine mammals have been 
documented at Southeast Farallon Island since the 1980s, providing a 
relatively long time series of information. Over the last 30 years 
researchers working at the islands have published a number of papers 
reporting an increase in white shark abundance based on the increased 
incidence of attacks on pinnipeds. Ainley et al. (1996) suggested that 
white shark populations were increasing in abundance in association 
with the increase in northern elephant seals (Mirounga angustirostris) 
at Southeast Farallon Island and they also reported an increase in the 
size of white sharks. Elephant seals were first seen at the Islands in 
the 1970s after which the presence of white sharks increased (Lowry, 
1994). At a 1996 white shark symposium Pyle et al. (1996) and Klimley 
and Anderson (1996) concluded that the white shark population at 
Southeast Farallon Island was increasing, given the increased number of 
observed attacks on pinnipeds, even after taking into account the 
increased abundance of pinnipeds during the 1970s and 1980s. Brown et 
al. (2010) recently found that variation in the number of white shark 
attacks on northern elephant seals was correlated with the number of 
elephant seals present during their autumn haul-out to give birth, mate 
and molt. Their estimated shark abundance index explained very little 
of the annual variation in shark attacks, possibly indicating a stable 
shark population or that their index does not accurately reflect annual 
variation in shark abundance.
    White shark attacks on marine mammals in other locations have also 
increased. At San Miguel Island, which is the westernmost of the 
northern Channel Islands, annual surveys of pinniped populations have 
been ongoing for several decades to monitor their abundance (Jeff 
Harris, SWFSC, personal communication as cited in Dewar et al., 2013). 
Based on these surveys, the Channel Islands now support a population of 
over 100,000 California sea lions (Zalophus californianus). While it is 
only in the last couple years that there is evidence of attacks by 
white sharks on pinnipeds near the Channel Islands, the increase in 
shark-inflicted wounds is dramatic. In 2010 and in prior decades there 
were essentially no observed shark-inflicted wounds on California sea 
lions; however, in 2011 there were approximately 136 recorded bite 
marks, and in 2012 there were over 300 recorded bite marks (Jeff 
Harris, personal communication as cited in Dewar et al., 2013). The 
bite wounds were observed primarily in the summer (June-August) on 
juveniles and females, although the occurrence of scars early in the 
year suggest that attacks may occur year round. Not all bite wounds 
have been validated to be from white sharks, but the size and shape of 
the wounds are consistent with those from white sharks (Dewar et al., 
2013). The only other potential predator that could cause such wounds 
is a large mako shark, but this species is rarely observed or caught in 
this region and has not been observed near pinniped rookeries (Dewar et 
al., 2013).
    In addition to pinnipeds, white shark bite marks have been observed 
on southern sea otters (Enhydra lutris nereis) in coastal central 
California. Researchers at the U.S. Geological Survey Western 
Ecological Research Center (USGS-WERC) have reported a dramatic 
increase in the number of southern sea otter mortalities linked to 
white shark bites over the past 5 years, particularly in the region 
between Estero Bay and Pismo Beach, but also in Monterey Bay and areas 
north of Santa Cruz. Overall, the proportion of beach-cast sea otter 
carcasses in which shark bites are considered the primary cause of 
death has increased 3-4 fold from the long-term average, and shark-bite 
trauma has now become the single most frequently observed cause of 
death (USGS-WERC, unpublished data). Although definitive evidence for 
the species of shark responsible for the trauma is only available for 
10-20 percent of carcasses (i.e., where tooth fragments or tooth 
scrapes on bone are found), the evidence suggests that white sharks 
rather than other shark species are responsible for the observed 
mortality. A range of factors is likely impacting southern sea otter 
population trends in California; however, increased incidence of shark-
bite mortality is thought to be linked to sea otter population declines 
in some areas.
    In addition to trends in abundance and other indicators, 
information suggesting range expansion or contraction can provide 
insight into the status of a population. For example, the increase in 
the number of white sharks observed annually at Guadalupe Island since 
the early 1990s suggests the NEP population may be expanding its use of 
near-shore aggregation sites. The increased numbers of white shark bite 
marks on sea lions and southern sea otters in areas south of Monterey 
Bay also suggests an increased presence of white sharks in this region. 
While the coastal waters from the Channel Islands to Monterey Bay are 
clearly within the historical range of white sharks along the coast of 
California, the majority of white shark activity in the past 10 years 
has been reported in central California and at Guadalupe Island. There 
is no evidence to indicate that the increased abundance of white sharks 
at Guadalupe Island or in the region between the Channel Islands and 
Monterey Bay is due to sharks leaving the known aggregation sites in 
central California where they are typically found (Dewar et al., 2013).
    Based on a SEDM assessment, the BRT concluded that the available 
trend information indicates that the NEP white shark population is most 
likely stable or increasing rather than decreasing (Dewar et al., 
2013). The BRT also indicated that a stable or increasing NEP white 
shark population was consistent with: (1) the increased abundance of 
white shark prey resources (i.e., marine mammal and fish populations) 
over the past several decades; and (2) changes in the near-shore set 
gillnet and high seas drift gillnet fisheries over the past several

[[Page 40112]]

decades that have reduced fisheries-related impacts on the population. 
The BRT expressed some uncertainty about its assessment of white shark 
population trends because of the absence of historical information on 
abundance, uncertainty about female mortality levels, and uncertainty 
about whether changes in the range of the population are indicative of 
an overall increase in population size. Despite these uncertainties, 
the BRT found that the NEP white shark population is most likely stable 
or increasing (Dewar et al., 2013).

Abundance Estimates at Aggregation Sites

    Chapple et al. (2011) and Sosa-Nishizaki et al. (2012) analyzed 
white shark photo-ID data from central California (i.e., Farallon 
Islands and Tomales Point) and Guadalupe Island, respectively, using 
mark recapture methods to estimate the numbers of white sharks at the 
two aggregation sites. The combined abundance estimates from these two 
studies total approximately 339 subadult and adult white sharks. The 
BRT re-analyzed the original photo-ID data from these studies, as well 
as additional data provided by the researchers who had conducted the 
studies. The objectives of this re-analysis were to: (1) Examine both 
original data sets as well as the new data for white sharks from both 
sites; (2) evaluate potential bias in the population estimates by 
examining population demographics at both sites, including a key 
modeling assumption that all individuals have an equal probability of 
being captured (in this case photo-identified); (3) examine trends in 
abundance at Guadalupe Island, which had a much longer time series of 
data; and (4) calculate minimum estimates of the numbers of adult 
female white sharks and the male-to-female sex ratio at the two sites 
for use in extinction risk modeling.
    The central California dataset used in the re-analysis was the same 
as that used by Chapple et al. (2011), but included updated information 
about the sex of many individuals that was previously unknown. The 
Guadalupe Island dataset included 2 more years of data than were used 
by Sosa-Nishizaki et al. (2012), as well as information on the number 
of days of sampling effort per month over the 11-year study. The BRT 
conducted its mark recapture analysis of data for both sites using open 
models, which allowed the populations to change either through 
emigration, immigration or mortality. Detailed methods and information 
about models used in the analysis are provided in Dewar et al. (2013).
    The BRT's analysis indicated that the majority of white sharks at 
both aggregation sites were mature and that the sex ratio was strongly 
biased in favor of males at both sites (i.e., 1.6 to 1 at Guadalupe 
Island and 3.8 to 1 at the central California sites), although there 
were significant seasonal changes in the sex ratio at Guadalupe Island 
(Dewar et al., 2013). Estimates of mature adults at the two aggregation 
sites ranged from approximately 85 percent in central California to 90 
percent at Guadalupe Island. A total of 131 white sharks were recorded 
by photo-ID studies at the central California sites from 2006-2008. Re-
analysis of the data by the BRT generated a 3-year super-population 
estimate (i.e., an estimate of all the individuals that were observed 
at the site during the study, including those that have died or 
emigrated from the site) of 166 white sharks, which is comparable to 
the open population model estimate of 156 white sharks reported by 
Chapple et al. (2011) and within the confidence limits of the larger 
closed population model estimate of 219 white sharks that they also 
reported (Dewar et al., 2013). A total of 142 white sharks were 
recorded by photo-ID studies at Guadalupe Island from 2001-2011 and the 
BRT's re-analysis of these data generated a super-population estimate 
of 154 white sharks for the study period, which is higher than the 
estimate of 120 white sharks reported by Sosa-Nishizaki et al. (2012), 
presumably because additional data were analyzed. The BRT's analysis of 
the Guadalupe Island data also provided annual estimates of white shark 
abundance, which demonstrated an increasing trend in abundance over the 
study period, with males nearly doubling in abundance and females 
initially increasing in abundance followed by a period of stable 
numbers (see Evaluation of Trend Information section).

Evaluation of Bias in White Shark Sex Ratios and Adult Population Size

    The BRT's estimates of white shark abundance at the central 
California and Guadalupe Island aggregation sites were within the 
bounds of those previously estimated by Chapple et al. (2011) and Sosa-
Nishizaki et al. (2012). However, the BRT was concerned about potential 
sources of bias associated with these abundance estimates based on its 
examination of demographic and other data, and concluded that they were 
unlikely to represent a realistic estimate of the abundance of subadult 
and adult white sharks in the entire NEP population. Therefore, the BRT 
undertook an effort to more carefully evaluate bias in the estimated 
sex ratios at the two sites and bias in estimation of the total NEP 
population abundance. This information was then used to develop a range 
of plausible population abundance levels for the NEP white shark 
population that were subsequently used in the BRT's extinction risk 
modeling.

Sex Ratio Bias

    Males dominate the available photo-ID data from the central 
California and Guadalupe Island aggregation sites, and therefore the 
sex ratios at both sites are highly skewed in favor of males. Given the 
apparent skew in the sex ratios at both aggregation sites and concerns 
about bias in the photo-ID studies, the BRT concluded that the direct 
empirical estimates of female abundance at the two sites likely 
underestimated the actual abundance of females, both at the sites and 
in the NEP population as a whole. The BRT identified several possible 
reasons for the observed sex ratio skew which also suggest the actual 
abundance of white sharks in the NEP has been underestimated.
    First, white sharks may exhibit sexual segregation as do some other 
sharks in the family Lamnidae (e.g., salmon and mako sharks). In nearly 
all places where white sharks have been surveyed, the sex ratio of pups 
both in utero and in the environment is close to parity or 1:1 (Dewar 
et al., 2013), but the sex ratio of older life stages (i.e., juvenile, 
subadult and adult) is skewed in favor of males (e.g., on the U.S. east 
coast, Casey and Pratt, 1985; and in New Zealand, C. Duffy, personal 
communication with Heidi Dewar in Dewar et al., 2013). A recent study 
in South Africa found a skewed male-to-female sex ratio of 3 to 1 with 
both seasonal and spatial shifts in the sex ratios of juvenile and 
subadult white sharks over relatively small spatial scales (Robbins, 
2007). In the NEP, sexual segregation is also apparent offshore, with 
females making more dispersed offshore movements than males, which have 
a more focused distribution (Jorgensen et al., 2010; Domeier and Nasby-
Lucas, 2012). Second, some females may not be sampled at the central 
California and Guadalupe Island aggregation sites because they arrive 
later in the season after most of the photo-ID sampling effort has 
ended. Due largely to weather conditions, the majority of the sampling 
effort at these sites occurs opportunistically over a period of 2 to 4 
months in the late summer and fall, which does not cover the entire 
period that white sharks are present. Based on

[[Page 40113]]

work at Guadalupe Island, the observed male-to-female sex ratio shifts 
from 8 to 1 in August to 0.9 to 1 in November (Nasby-Lucas and Domeier, 
2012), indicating that sampling at different times can influence 
estimates of the observed sex ratio in the local population. Third, it 
is possible that some females at the aggregation sites are simply not 
available to be sampled for behavioral reasons (see Sosa-Nishizaki et 
al., 2012). Lastly, mature females have a presumed 18-month gestation 
period and many do not return each year to the aggregation sites. At 
the central California sites, for example, this behavior combined with 
the relatively short time series of available data may have resulted in 
poor estimation of the capture probability for females and consequently 
an underestimate of female abundance.
    Because of the likely sex ratio bias associated with the white 
shark population estimates at the central California and Guadalupe 
Island aggregation sites, the BRT undertook a SEDM assessment to 
evaluate the relative plausibility of different sex ratio alternatives 
at each site. For each site, the least skewed alternative the BRT 
considered was a male to female sex ratio of 1 to 1 and the most skewed 
alternative was the sex ratio derived empirically from the BRT's mark-
recapture analysis of the available data. Intermediate sex ratio 
alternatives were also considered for each aggregation site. Based on 
this assessment, the BRT concluded that the actual sex ratios at both 
sites were most likely not as strongly skewed in favor of males as 
suggested by the photo-ID data and that there are more females in these 
populations than suggested by mark-recapture analysis of the photo-ID 
data (Dewar et al., 2013). The most important factor influencing the 
BRT's assessment was the timing of the sampling season at both sites 
relative to the late arrival of females, which would result in under 
sampling of females.

Population Abundance Bias

    The BRT concluded that there are several factors which bias the 
estimation of white shark abundance in the NEP and that also indicate 
there are more adult female white sharks, and hence a larger overall 
NEP population, than have been estimated at the central California and 
Guadalupe Island aggregation sites (Dewer et al., 2013).
    First, the abundance estimates for the central California and 
Guadalupe Island aggregation sites do not include all white sharks in 
those areas. For example, abundance estimates at the central California 
sites do not include white sharks at other locations that are 
documented to be hotspots, such as A[ntilde]o Nuevo State Park. There 
is a long history of white shark activity at this location, which is 
the site of the largest mainland breeding colony of northern elephant 
seals. In addition, acoustic tagging studies in central California 
(Jorgensen et al., 2010) have shown that some individual white sharks 
exhibit site fidelity to particular coastal sites such that they were 
unlikely to have been observed by the photo-ID studies conducted at the 
Southeast Farallon Island or Tomales Point sites. Similarly, photo-ID 
studies of white sharks have been conducted only at one of several 
locations around Guadalupe Island where they are known to occur, 
suggesting that not all white sharks at the island have been observed 
by the photo-ID studies.
    Second, white sharks may occupy unknown or previously unoccupied 
areas in the NEP. For example, there appears to be an increased 
occurrence of white sharks near the northern Channel Islands in 
southern California and in some portions of central California. Other 
potential aggregation sites where pinnipeds are known to be common and 
white sharks may occur include the Coronado Islands and Cedros Island 
in Mexico, both of which are areas where Mexican fishermen have 
reported large white sharks (Sosa-Nishizaki, personal communication 
cited in Dewar et al., 2013). White sharks have also been reported in 
areas away from the main aggregation sites off Alaska, British 
Columbia, Washington, Oregon, California, Baja California and the Gulf 
of California (Klimley, 1985; Martin, 2005; Galv[aacute]n-Maga[ntilde]a 
et al., 2010). Although some white sharks tagged at the two aggregation 
sites have been observed to visit other coastal sites (S. Jorgensen, 
personal communication in Domeier and Nasby-Lucas, 2012), the data are 
limited and information on the extent of coastal areas used by white 
sharks tagged at these sites is still unknown.
    Third, recent data using isotopes to characterize the diet of 
different life stages of white sharks suggest that not all adult white 
sharks transition to preying on marine mammals (Kim et al., 2012), and 
thus these individuals may not be as likely to occur near pinniped 
aggregations and be available for observation.
    Fourth, based on catch, attack and stranding data, some white 
sharks do not appear to undergo annual offshore migrations (Ainley et 
al., 1985; Klimley, 1985). Very few satellite-tagged white sharks have 
remained along the coast, suggesting that white sharks not undergoing 
offshore migrations may represent a portion of the NEP that is not 
being sampled. It is possible that many of the white sharks remaining 
along the coast are subadults rather than adults, but the possibility 
that some adults remain in coastal areas year round cannot be ruled 
out.
    Lastly, the high diversity of mtDNA haplotypes found in the NEP 
white shark population suggests the population may be much larger than 
indicated by the mark-recapture estimates for the central California 
and Guadalupe Island aggregation sites (see Genetic Information on 
White Shark Population Structure and Population Size section).
    The BRT used a SEDM assessment to evaluate different levels of 
possible bias associated with extrapolating the adult female population 
estimates from the two aggregation sites to an overall adult female 
abundance estimate for the NEP white shark population. The BRT 
considered four levels of potential bias in this assessment: (1) No 
bias because all white sharks in the NEP are available for sampling at 
the central California and Guadalupe Island aggregation sites; (2) a 
bias indicating there are approximately 20 percent more adult females 
in the NEP population than estimated by the mark-recapture studies at 
the aggregation sites because a small portion of the population is not 
available for observation at those sites; (3) a bias indicating there 
are approximately two times more adult females in the NEP population 
than estimated by the mark-recapture studies at the two sites because 
white sharks occur at other sites or areas that are not sampled and/or 
because the timing of sampling at the aggregation sites misses a key 
portion of the population; and (4) a bias indicating there are up to 10 
times more adult female white sharks in the NEP population than 
estimated by the mark-recapture studies, as suggested by the high 
haplotype diversity and the fact that most white sharks in the NEP 
population are not available for sampling at the aggregation sites.
    Based on its assessment, the BRT concluded that the abundance of 
female white sharks in the NEP population is most likely at least 2 
times larger and possibly much larger than the combined abundance 
estimate for the central California and Guadalupe Island aggregation 
sites. Several factors influenced the BRT's evaluation and conclusion 
regarding abundance bias. First, there are areas where white sharks are 
consistently observed, such as A[ntilde]o Nuevo State Park and possibly 
the Channel Islands, which have not been sampled. Second, the BRT 
thought it

[[Page 40114]]

was plausible that some females never visit either of the two known 
aggregation sites. Finally, the high level of haplotypic diversity in 
white sharks from the NEP indicates that the population is likely much 
larger than indicated by the population estimates for the two 
aggregation sites alone (see Genetic Information on White Shark 
Population Structure and White Shark Population Size section).

Female Abundance Estimates for Fisheries Risk Assessment Modeling

    The BRT developed a range of plausible adult female abundance 
levels for the NEP white shark population for use in modeling the 
extinction risk associated with fisheries impacts. As described in 
Dewar et al. (2013), the BRT developed 48 estimates of female abundance 
for the NEP white shark population using the 12 combinations of sex 
ratio bias (i.e., four at the central California sites and three at 
Guadalupe Island) and four levels of population abundance bias that 
were evaluated by SEDM. Each of the female abundance estimates was 
weighted by the SEDM assessments for sex ratio and abundance bias and 
then grouped into four adult female abundance levels as follows: (1) 
Less than 125 adult females; (2) 125-200 adult females; (3) 200-400 
adult females; and (4) greater than 400 adult females. The fisheries 
risk assessment modeling evaluated each of these female abundance 
levels as well as the minimum population estimate of 47 adult females 
derived from the BRT's re-analysis of photo-ID data at the central 
California and Guadalupe Island aggregation sites (Dewar et al., 2013). 
The sum of the weights for individual female abundance estimates within 
each of the four abundance levels represented the BRT's assessment of 
the most likely adult female abundance level in the NEP white shark 
population as a whole. Based on this analysis, the BRT concluded that 
the adult female abundance in the NEP was most likely in the range of 
200-400 adult individuals (see Dewar et al., 2013 for more detailed 
information).
    The BRT reassessed the most likely adult female abundance a second 
time after the initial extinction risk modeling indicated that the 
minimum population estimate of 47 adult females was unrealistic given 
current estimates of fishery mortality for YOY and juvenile white 
sharks. Based on this second SEDM assessment, which changed the weights 
assigned to each of the 48 adult female abundance estimates, the BRT 
concluded that the adult female abundance in the NEP was at least in 
the range of 200-400 adult females and most likely greater than 400 
adult females (Dewar et al., 2013).

Fisheries Risk Assessment Modeling

    The BRT conducted population modeling to assess how fisheries-
related mortality would impact NEP white shark population growth rates 
and how changes in population growth rates would affect adult female 
population abundance over time. A brief summary of the BRT's analytical 
approach is presented below with more detailed information presented in 
Dewar et al. (2013).

Analytical Approach

    The BRT's fisheries risk assessment modeling for the NEP white 
shark population was based on: (1) Estimates of the maximum potential 
productivity of the population (i.e., intrinsic population growth rate) 
using information on key vital parameters of white sharks (i.e., 
reproduction and survival rates); (2) estimates of adult female white 
shark population abundance (see Female Abundance Estimates for 
Fisheries Risk Modeling section); and (3) estimates of current YOY, 
juvenile and adult white shark mortality in U.S and Mexican gillnet 
fisheries. Estimates of adult female abundance in the NEP white shark 
population, rather than total population abundance estimates, were used 
in the modeling because female reproduction (i.e., pup production) is a 
key factor controlling population growth rate and the purpose of the 
analysis was to evaluate how estimated fisheries mortality affects 
white shark population growth rates and population abundance over time.
    Estimates of potential population productivity are fundamental to 
modeling how threats such as fisheries-related mortality may impact 
population growth because populations with higher potential 
productivity can sustain higher levels of mortality. Annual rates of 
population growth can be calculated using information on a species' 
vital rates (i.e., age-specific reproduction and survival rates) 
assuming the relative proportion of the population in different age 
classes is stable. Using a variety of information sources, the BRT 
developed estimates of age-specific reproduction and survival rates for 
female white sharks and then used this information to develop estimates 
of the population's maximum growth rate.
    As discussed in the Female Abundance Estimates for Fisheries Risk 
Assessment Modeling section, the BRT defined four adult female 
abundance levels for the NEP white shark population based on its 
assessment of sex ratio and abundance bias. Extinction risk modeling 
analyzed adult female abundance within these four abundance levels, as 
well the minimum adult female abundance estimate (i.e., 47 adult 
females) derived from the BRT's mark-recapture analysis of photo-ID 
data from the two aggregation sites.

Modeling Analysis

    The BRT developed estimates of YOY and juvenile white shark 
fishery-related mortality using current fishery bycatch estimates in 
U.S. and Mexican gillnet fisheries. Because the BRT did not have 
estimates of actual adult female white shark bycatch, a SEDM assessment 
was used to evaluate potential levels of adult female mortality in U.S. 
and Mexican nearshore fisheries, as well as high seas IUU fishing. 
Based on available information informing potential fisheries-related 
mortality levels for adult females (see Appendix H in Dewar et al., 
2013), the BRT evaluated adult female mortality levels ranging from 0 
to 10 adults females per year. Based on its assessment, the BRT 
concluded that adult female mortality was most likely between 1 and 5 
adult females per year. Fishery-related mortality for each life stage 
(i.e., YOY, juveniles and adults) was incorporated into the modeling 
analysis.
    The BRT used the information on maximum population growth rates, 
estimates of adult female population abundance, and fishery mortality 
to model the impact of fishery bycatch on the adult female population 
in the NEP in three stages. First, bycatch rates and mortality rates 
for YOY and juvenile white sharks were calculated for each of the four 
adult female abundance levels defined by the BRT. These rates were then 
used to calculate how the estimated fisheries mortality for each of the 
four adult female abundance levels impacted the maximum population 
growth rate and the probability of population decline over time. 
Second, estimates of adult female mortality were added to the YOY and 
juvenile mortality estimates for each of the four adult female 
abundance levels and the impact on the maximum population growth rate 
and probability of population decline were re-calculated. Finally, the 
maximum population growth rates for each of the four adult female 
abundance levels were reduced by the estimated fishery mortality for 
all life stages and then used to project adult female population 
abundance into the future using a stochastic age-structured density-
dependent growth model. These modeling results were then used to 
calculate the probability that adult female abundance would decline 
below

[[Page 40115]]

defined population abundance thresholds over specific time horizons.

Definition of Risk Categories and Foreseeable Future

    The BRT defined four levels of overall extinction risk (i.e., high, 
medium, low and very low) for its analysis. The specific criteria for 
each level of extinction risk were based on the current estimated 
abundance of the NEP white shark population, white shark population 
trajectories over specific time horizons, and the probability of a 
white shark population decline below specified thresholds. To evaluate 
population trajectories, the BRT used a range of time horizons (i.e., 
40, 60 and 100 years) that were based on the white shark generation 
time (~20 years). The 40-year time horizon (or two white shark 
generations) was defined by the BRT as the foreseeable future for the 
white shark risk assessment and the 60-year (3 white shark generations) 
and 100-year (5 white shark generations) time horizons were used for 
different levels of risk. The BRT also defined two white shark 
population abundance levels corresponding to ``near extinction'' (50 
mature individuals) and ``dangerously small'' (250 mature individuals), 
which are discussed in more detail in Dewar et al., (2013). The two 
highest risk categories have criteria that are intended to address 
risks faced by a declining population and risks faced by small 
populations, both of which are indicators that a species is potentially 
at a high risk of extinction.
    The BRT considered the foreseeable future in its analysis to be the 
timeframe over which predictions about the future status of the NEP 
white shark population could reliably be made. In quantifying the 
foreseeable future (40 years), as well as other timeframes used in the 
analysis, the BRT considered several factors to be particularly 
relevant. First, overutilization (i.e., fishery related mortality) is 
the most significant potential threat to the population. Second, the 
primary life history stage or age category suffering mortality in the 
U.S. and Mexican gill net fisheries that impact the population are YOY 
individuals. Third, white sharks are long-lived species. Given these 
factors, the BRT concluded that the definition of foreseeable future 
should be based on white shark generation time since fishery impacts on 
YOY individuals will influence population abundance and risk on that 
timeframe. The BRT concluded that it was appropriate to address the 
threat from overutilization (i.e., fishery mortality) over longer 
timeframes (60 and 100 years) based on other precedents for defining 
and assessing extinction risk (Dewar et al., 2013).
    Based on these considerations, the BRT defined the following 
extinction risk levels for evaluating the status of the NEP white shark 
population:
    High Risk: The population is at high risk if it has a 5 percent 
chance of falling below 50 mature individuals (25 mature females) in 60 
years (3 generations) or the current population is less than 250 mature 
individuals (125 mature females).
    Medium Risk: The population is at medium risk if it has a 5 percent 
chance of falling below 50 mature individuals (25 mature females) in 
100 years (5 generations) or the population has a 5 percent chance of 
falling below 250 mature individuals (125 mature females) in 40 years.
    Low Risk: The population does not meet the criteria for medium or 
high risk, but the probability of a net population decline within 100 
years (Nt=100 < Nt=0) is greater than 10 percent.
    Very low Risk: The population does not meet any of the above 
criteria for high, medium, or low risk and the population has a high 
probability of being stable or increasing.

Modeling Results

    The BRT's estimation of YOY and juvenile mortality and its impact 
on maximum population growth rates for the minimum adult female 
abundance estimate from the aggregation sites and the four adult female 
abundance levels that were defined resulted in two key findings. First, 
the estimates of annual YOY and juvenile fishery-related mortality for 
the minimum population estimate of 47 adult females were equal to or 
greater than the total number of pups and 1-year-old individuals that 
would be expected to be produced by a population with that number of 
adult females. The BRT found this result to be unrealistic and 
concluded that the actual adult female abundance in the NEP population 
must be substantially higher than the population estimates based on 
photo-ID data from the two aggregation sites. For this reason, the BRT 
excluded this minimum adult female population abundance estimate from 
all further analysis. Second, the analysis indicated that there was a 
low or negligible probability that a NEP white shark population having 
at least 125-200 adult females would decline, given the estimated YOY 
and juvenile mortality from fisheries.
    The BRT's estimation of the combined fisheries mortality for YOY, 
juvenile and adult females for the four adult female abundance levels 
and its impact on maximum population growth rates resulted in several 
findings. First, there was a high probability that a white shark 
population having less than 125 adult females would decline, given the 
estimated YOY and juvenile mortality and any level of adult female 
mortality. Second, there was a small or trivial probability that a 
white shark population having at least 125-200 adult females would 
decline to near extinction within 60 to 100 years, given the estimated 
YOY and juvenile mortality and a low level (1 or 2 individuals per 
year) of adult female mortality. If adult female mortality were higher 
(in excess of five individuals), which the BRT felt was less plausible, 
then the probability of adult female population decline would be 
higher. Third, there was a very low probability that a white shark 
population having at least 200 adult females would decline given the 
combined fishery mortality estimates for all life stages.
    Overall, the BRT's modeling results indicate that if the NEP white 
shark population presently has 200 or more adult females, there is a 
low to very low risk of extinction associated with fisheries mortality 
on adult females, YOY, and juvenile white sharks over any of the time 
periods that were analyzed. If adult female abundance is actually lower 
than 200 adult females, the risk to the population would range from 
medium to high depending on the current population size and mortality 
of adult females. Detailed modeling results are presented in Dewar et 
al. (2013).

Overall BRT Extinction Risk Conclusions

    The BRT conducted a final SEDM assessment to evaluate overall 
extinction risk for the NEP white shark population that considered all 
information from the status review report. This information included 
the assessment of threats to the population, direct and indirect 
indicators of population trends, information on population abundance, 
including updated mark-recapture analysis, genetic information related 
to population size, the evaluation of factors biasing the available 
population abundance estimates, and the results of extensive population 
modeling to assess risks associated with fisheries bycatch mortality. 
Based on this information and uncertainty about the future, the BRT 
allocated plausibility points among the four risk categories previously 
defined (see Definition of Risk Categories and Foreseeable Future 
section). The BRT allocated the vast majority of its plausibility 
points in the low and very low risk categories (86 percent of 
plausibility points--see Table 4.17 in

[[Page 40116]]

Dewar et al., 2013) indicating that the NEP white shark population is 
currently considered to be larger than 250 mature individuals (see 
Female Abundance Estimates for Fisheries Risk Assessment Modeling 
section), that the population is likely to be stable or increasing in 
abundance (see Evaluation of Trend Information section), and that the 
population is not likely to fall below critical population thresholds 
in the foreseeable future (40 years) or beyond (60 and 100 years) (see 
Fisheries Risk Assessment Modeling section). Based on its overall risk 
assessment and the results of this SEDM assessment, the BRT concluded 
that the NEP white shark population is likely to be at a low to very 
low risk of extinction and is likely to remain so in the foreseeable 
future.
    The level of extinction risk facing a population depends on 
information about its abundance, trends in abundance or other 
population indicators, potential threats to the population over time 
and uncertainty about the future. Fisheries-related mortality was the 
only factor the BRT found to be a potentially important threat to the 
NEP white shark population. The BRT acknowledged that other threats 
such as physiological effects of contaminants in the environment or the 
trophic implications of ocean acidification from climate change could 
adversely affect the population, but these threats were considered to 
have relatively minor population-level effects within the foreseeable 
future compared to direct fisheries-related mortality. The BRT 
concluded that depletion of white shark prey (e.g., pinnipeds and 
various fish species) from human activities may have had historical 
impacts on the NEP white shark population, but because pinniped 
populations have increased substantially over the last several decades 
and many fish stocks preyed upon by white sharks have similarly 
recovered or are in the process of recovering, this factor is no longer 
a threat and is not likely to become one in the foreseeable future.
    The BRT concluded that the available information informing trends 
in abundance of the NEP white shark population is most consistent with 
a stable or increasing population. White shark CPUE has increased since 
the mid-1990s in the U.S. west coast set gillnet fishery, which would 
be expected for an increasing population. This period of increasing 
CPUE coincides with fishery management changes (i.e., high seas drift 
gillnet ban, time-area closures for gillnet fisheries offshore 
California, protection for white sharks by the State of California) and 
declining fishing effort that have reduced the potential for fishery 
interactions with white sharks. Increasing abundance of white sharks at 
Guadalupe Island and the increased incidence of white shark attacks on 
marine mammals at different sites along the California coast also 
suggest that the NEP white shark population is increasing.
    Modeling conducted by the BRT to assess the risks from U.S. and 
Mexican fisheries-related mortality on the NEP white shark population 
indicate that the population is likely at a low to very low risk of 
extinction and is likely to remain so in the foreseeable future if the 
population includes more than 200 or more adult females. As discussed 
below, the BRT determined that the current population includes at least 
200 adult females. However, the BRT's modeling results indicate that if 
there are fewer than 200 adult females in the population, then the 
population would be at a higher risk of extinction.
    The BRT indicated that there were several lines of evidence 
suggesting that the NEP white shark population includes at least 200 
adult females. The most important evidence comes from its analysis of 
fisheries mortality. Based on its analysis, the BRT concluded that the 
level of YOY and juvenile bycatch mortality estimated for U.S. gillnet 
fisheries and reported for Mexican gillnet fisheries is inconsistent 
with the NEP white shark population being smaller than several hundred 
females. If adult female abundance is presently less than 200 
individuals, then the estimated fisheries bycatch would correspond to 
removing on the order of 20 to 70 percent of the estimated annual pup 
production, which the BRT considered highly unlikely for several 
reasons. First, population removal rates for sharks in fisheries using 
more selective fishing gear than gillnets (e.g., pelagic longlines) are 
probably less than 20 percent (Worm et al., 2013). Second, for 
populations of marine mammals and sea turtles known or suspected to be 
declining because of high bycatch mortality, the mortality rate on age 
classes affected by gillnet bycatch is typically less than 10 percent. 
Third, even a 20 percent mortality rate on YOY and juveniles seems 
unlikely given that most of the estimated fishery mortality comes from 
a small number of fishermen (i.e., artisanal fishermen) that operate in 
only a relatively small portion of the population's nursery habitat 
(e.g., Sebasti[aacute]n Vizca[iacute]no Bay). Although YOY white sharks 
have been found to move from the SCB to nursery habitat in Baja 
California, and thus could subject more of the YOY population to 
fishery impacts in Mexico, the available information regarding such 
movements is limited and there is no information indicating what 
portion of the population undertakes such movements. Based on these 
considerations, the BRT concluded that if the U.S. and Mexican gillnet 
fisheries are removing less than 20 percent of the annual pup 
production, as seems most likely, the estimated level of YOY and 
juvenile bycatch from fisheries is most consistent with a NEP white 
shark population that includes at least several hundred adult females. 
Finally, the BRT found that the available information on the haplotyic 
diversity for the NEP white shark population was most consistent with a 
NEP white shark population numbering several hundred or more adult 
females (see Genetic Information on White Shark Population Structure 
and Population Size section).
    If the current adult female abundance of white sharks in the NEP 
exceeds 200 individuals, as the BRT has concluded is most likely the 
case, then the empirical estimates of subadult and adult white shark 
abundance at the central California and Guadalupe Island aggregation 
sites do not represent an accurate estimate of abundance for the entire 
NEP population (Dewar et al., 2013). The BRT determined that this 
underestimate of the NEP population abundance could be explained by a 
combination of highly plausible factors including: (1) Under sampling 
of females at the aggregation sites due to a temporal mismatch of 
sampling effort with respect to the timing of female arrival at the 
sites; (2) under sampling of females relative to males at the 
aggregation sites because of spatial-behavioral factors (see Soza-
Nishizaki et al., 2012); (3) under sampling of males and/or females at 
the aggregation sites because of strong site fidelity or area 
preferences by one or both sexes around pinniped rookery areas (see 
Jorgensen et al., 2010) and the use of fixed sampling locations; and 
(4) under sampling of both males and females that do not use the 
surveyed aggregation areas (e.g., individuals that use other pinniped 
rookery areas or do not feed substantially on marine mammal prey).

Summary of Factors Affecting the NEP White Shark Population

    Section 4(a)(1) of the ESA and our implementing regulations (50 CFR 
part 424) state that we must determine whether a species is endangered 
or threatened because of any one or a combination of the following 
factors: (1) The present or threatened destruction,

[[Page 40117]]

modification, or curtailment of its habitat or range; (2) 
overutilization for commercial, recreational, scientific, or 
educational purposes; (3) disease or predation; (4) inadequacy of 
existing regulatory mechanisms; or (5) other natural or man-made 
factors affecting its continued existence. This section summarizes 
findings regarding threats to the NEP white shark population. 
Additional information regarding threats to the population can be found 
in the BRT's status review report (Dewar et al., 2013) and a report 
prepared by NMFS' Southwest Region (NMFS, 2013).

A. The Present or Threatened Destruction, Modification, or Curtailment 
of Its Habitat or Range

    Potential threats to the habitat of the NEP white shark population 
include pollution, depletion of white shark prey species, ocean 
acidification, and ocean warming associated with climate change. Each 
of these threats is discussed in the following sections.

Pollution

    The SCB is important habitat for the NEP white shark population and 
serves mainly as a nursery area for YOY and juvenile white sharks. The 
SCB has a history of pollution due to discharges from publicly owned 
treatment works as well as non-point sources; however, pollutant inputs 
to this area from all sources have decreased since the 1970s despite 
increasing urbanization and human population growth along the southern 
California coast (Raco-Rands, 1999, cited in Schiff et al., 2000). 
Pollutants introduced into the SCB include heavy metals (e.g., 
mercury), chlorinated hydrocarbons (e.g., pesticides), petroleum 
hydrocarbons (e.g., polycyclic aromatic hydrocarbons or PAHs), 
nutrients, and bacteria (Schiff et al., 2000). Although banned from use 
in the 1970s, legacy pollutants such as DDT and PCBs remain in the SCB 
sediments (Schiff et al., 2000) and have likely been distributed 
throughout the area by water and sediment transport (Schiff et al., 
2000).
    Mull et al. (2012) observed high levels of mercury, DDT and PCBs in 
the tissues of YOY and juvenile white sharks caught in the SCB. 
According to Mull et al. (2013), the high contaminant levels observed 
in white sharks from the SCB are thought to be linked to maternal 
offloading. Although the observed contaminants could potentially impair 
the physiological and reproductive development of white sharks, there 
is no information indicating that contaminants such as organochlorines 
adversely impact sharks (Fowler et al., 2005; Mull et al., 2012). In 
addition, no hepatic lesions or other visible effects have been 
observed in white sharks in the SCB (K. Lyons, CSULB, personal 
communication cited in Dewar et al., 2013).
    These contaminants may also affect the prey species used by various 
life stages of the NEP white shark population. Adult white sharks are 
typically characterized as marine mammal predators (e.g., northern 
elephant seals, harbor seals, California sea lions), but they also prey 
upon a variety of bony fish species (ranging from benthic rockfish and 
flatfish to large pelagic species such as swordfish and bluefin tuna), 
other elasmobranchs, cephalopods, crustaceans, and even some bird 
species (Fowler et al., 2005). Both marine mammal populations and some 
fish species in the SCB have been found to have high tissue levels of 
contaminants such as mercury, DDT, and PCBs, but impacts of the 
contamination on these populations is unclear. Since the 1970s the 
incidence of fish diseases linked to these contaminants has declined, 
most likely due to reductions in pollutant input into the SCB (Schiff 
et al., 2000) and there is strong evidence that most fish species 
preyed upon by white sharks have been increasing in abundance (Dewar et 
al., 2013). Although pinniped species in the SCB continue to have high 
tissue concentrations of DDTs and PCBs (Blasius and Goodmanlowe, 2008), 
their populations have exhibited dramatic increases in abundance over 
the past several decades (Schiff et al., 2000; Carretta et al., 2013), 
suggesting that contaminants have had little impact on the populations.
    Overall, contaminants continue to be present in the SCB and are 
found in white sharks and their prey species, and thus have the 
potential to affect the health of white sharks. However, the potential 
threat from contamination has likely decreased over time as a result of 
substantial reductions in pollutant inputs into the SCB since the 
1970s. Potential impacts to the NEP white shark population from this 
contamination remain uncertain.
    Another source of pollution that may affect the NEP white shark 
population is marine debris. Marine debris is known to concentrate in 
an area of the North Pacific Ocean referred to as the ``Great Pacific 
Garbage Patch'', but this area has a limited overlap with the offshore 
habitat used seasonally by male and female white sharks. Debris may 
also be a concern in other areas used by white sharks, including the 
SCB, as well as the aggregation areas in central California and at 
Guadalupe Island offshore Baja California. The main risks of marine 
debris to white sharks are entanglement and ingestion. Plastics are of 
particular concern because they make up a large portion of the marine 
debris in the oceans (Moore et al., 2001; Derraik, 2002), can be 
transported over long distances, decompose slowly, cannot be digested, 
and have been found to accumulate pollutants such as PCBs, DDTs, and 
polycyclic aromatic hydrocarbons (Moore et al., 2001; Rios et al., 
2010).
    The BRT found no evidence that white sharks observed off Guadalupe 
Island or caught in southern California gillnet fisheries were reported 
to be entangled in marine debris, and therefore concluded that the risk 
of entanglement was likely to be low (Dewar et al., 2013). Compagno 
(2001) indicated that inedible garbage has occasionally been found in 
the stomachs of white sharks (referring to the global population, not 
the NEP population), but that white sharks are not generally known to 
ingest debris. The BRT noted that sharks are capable of evacuating 
their stomachs and have been observed to swallow satellite tags and 
spit them back up (Dewar et al., 2013). These capabilities are likely 
to help white sharks minimize the impacts of ingesting marine debris. 
It is not known to what extent white sharks are feeding when they are 
offshore and in the area that overlaps with the garbage patch. Stable 
isotope analysis of dermal and muscle tissue samples taken from small 
to large white sharks at coastal aggregation sites in central 
California indicates that white sharks feed when offshore, but at a 
lower rate than in coastal habitats (Carlisle et al., 2012). It is also 
possible that the primary purpose of these offshore migrations is 
reproduction (Jorgensen et al., 2010 and 2012; Carlisle et al., 2012). 
Without specific information about the extent to which white sharks 
forage in offshore waters and what they are feeding on, it is difficult 
to evaluate the potential risk of ingestion of marine debris by white 
sharks in offshore waters. Overall, marine debris may pose a potential 
risk to NEP white sharks via entanglement or ingestion, but the risk is 
likely to be low (Dewar et al., 2013).

Depletion of Prey Resources Due to Human Exploitation

    Several species of pinnipeds including northern elephant seals, 
California sea lions, Pacific harbor seals and Guadalupe fur seals are 
an important part of the diet of white sharks in the NEP. Historically, 
these species were subject to human exploitation, and on the west coast 
of

[[Page 40118]]

North America they were hunted to near extinction (Townsend, 1931 as 
cited in NMFS, 2000; NMFS, 2007) or greatly reduced in abundance (NMFS, 
2011a). These species have been protected since 1972 under the Marine 
Mammal Protection Act (MMPA) and are no longer subject to harvest. 
Population trends for these species began increasing in the 1950s and 
1960s and have continued to increase under MMPA protections (NMFS, 
2000; Gallo-Reynoso et al., 2005; NMFS, 2007; 2011a; 2011b; Carretta et 
al., 2013). The most recent stock assessments estimate that northern 
elephant seals have almost reached their carrying capacity for pups per 
year and that harbor seals may be at carrying capacity. Guadalupe fur 
seals that are found mainly at Guadalupe Island have been increasing at 
an average rate of about 13.7 percent each year (NMFS, 2000). Thus, 
even though human exploitation significantly reduced these pinniped 
species in the past, they have been increasing in abundance over the 
past several decades and are not thought to be currently limiting the 
NEP white shark population (Dewar et al., 2013).
    The NEP white shark population also forages on a diversity of other 
species that may be affected by human exploitation, including a wide 
range of bony fishes, elasmobranchs (sharks, skates and rays) and 
invertebrates (Klimley, 1985; Compagno, 2001). Many of these prey 
species are either targeted directly in fisheries or are caught 
incidentally in fisheries and have been reduced in abundance. For 
example, gillnet fisheries targeting white seabass, angel sharks and 
California halibut offshore of California expanded in the 1970s, 
leading to declines in their abundance, as well as the abundance of 
other species, in the 1980s and 1990s. The State of California 
responded to these population declines by adopting regulations in 1994 
that prohibited the use of gillnets in California state waters (i.e., 
within 3 nautical miles of shore). As a result of these regulatory 
changes, populations of many of these species have increased in 
abundance, including white seabass, leopard shark and soupfin shark 
(Dewar et al., 2013).
    As part of its threats evaluation, the BRT evaluated the potential 
risks to YOY and juvenile white sharks in the NEP resulting from the 
depletion of known and potential prey species (Dewar et al., 2013). The 
BRT reviewed available stock assessment information for 23 species of 
fish and invertebrates either confirmed as white shark prey or as 
species that occur in YOY and juvenile habitats. The BRT found that 
many of the prey species have recovered from past overfishing and are 
currently considered to be healthy. Based on the status of these prey 
species and information suggesting that the white shark population as 
well as other species (e.g., pinnipeds, leopard sharks, soupfin sharks, 
and giant seabass) that use these prey species are increasing, the BRT 
concluded that these species are not limiting the NEP white shark 
population (Dewar et al., 2013).
    Overall, harvest activities historically affected the abundance of 
several fish and invertebrate prey resources that are known to be used 
by or are potentially used by the NEP white shark population. Many of 
these species experienced declines in abundance from the 1970s through 
the 1990s, but have since recovered. Based on the BRT's assessment of 
the white shark's fish and invertebrate prey resources, we conclude 
that prey species are not currently limiting the NEP white shark 
population.

Ocean Acidification

    Ocean acidification (i.e., a reduction in the pH of ocean waters 
due to the uptake of increased atmospheric carbon dioxide) has been 
identified as a potential concern for the nearshore waters of the 
California Current System (Gruber et al., 2012), an area which includes 
the nursery habitat and coastal aggregation sites for the NEP white 
shark population. Gruber et al. (2012) predicted that by 2050 oceanic 
uptake of carbon dioxide will lower the pH and the saturation state of 
aragonite (a mineral form of calcium carbonate used by calcifying 
organisms) in this area to levels well below the natural range. These 
predicted changes could affect fish species and the marine food web in 
the NEP as well as white sharks. For example, recent studies have shown 
that high carbon dioxide and low pH levels in seawater can impair 
olfactory responses and homing ability in clownfish (Munday et al., 
2009) and can lead to metabolic depression (Cruz-Neto and Steffensen, 
1997) or cardiac failure (Ishimatsu et al., 2004) in some other fish 
species. However, the extent of such impacts on individual species and 
how they may compensate for any impacts is uncertain. For example, some 
fish species may experience metabolic responses to elevated carbon 
dioxide levels at the cellular level, but are able to compensate for 
those responses on the organismic level, rendering them less sensitive 
to the effects of ocean acidification (Portner, 2008). No information 
is available regarding the impacts of low pH on sharks, and therefore, 
any potential effects on the NEP white shark population are highly 
speculative at this time (Dewar et al., 2013). Finally, it is difficult 
to extrapolate the effects of ocean acidification to the ecosystem 
level, such as changes in prey availability or changes in predator-prey 
relationships, particularly for a top-level predator such as the white 
shark that utilizes a broad range of prey (see Foraging Ecology 
section).

Climate Change

    Climate change is predicted to result in increased sea surface 
temperatures (SST) and associated shifts in the distribution and 
habitat of marine species. Hazen et al. (2012) predicted SST changes in 
the NEP ranging from less than 1[deg]C to 6[deg]C between 2001 and 
2100, with the largest temperature changes occurring in the North 
Pacific Transition Zone (at approximately 43[deg] N latitude) and 
minimal changes (less than 1[deg]C) occurring in the California Current 
System.
    Based on model predictions from Hazen et al. (2012), adult and 
subadult white shark and elephant seal habitat is predicted to increase 
by approximately 7 percent and 5 percent, respectively, between 2001 
and 2100, whereas California sea lion habitat is predicted to decrease 
by approximately 0.5 percent. The actual impact of climate change on 
the ecosystem is certainly more complicated than can be predicted by 
climate change models, but several factors suggest that white sharks 
have a greater capacity to adapt to, and could potentially benefit 
from, climate-related impacts to environmental conditions in the 
California Current System. First, white sharks are likely better able 
to adapt to climate-related changes due to their diverse diet and broad 
thermal tolerance (see O'Connor et al. 2009; Harley 2011; and Parmesan, 
2006 cited in Hazen et al., 2012). Second, the relatively small 
increases in SST predicted by Hazen et al. (2012) may allow white 
sharks to expand their habitat. For example, tagging studies show that 
YOY white sharks can use a broad range of water temperatures and spend 
more time in areas with warmer temperatures (Dewar et al., 2004; Weng 
et al., 2007a; Weng et al., 2007b; see also Klimley et al., 2002). 
Tagged YOY and juvenile NEP white sharks spent much of their time in 
the warmer surface waters of the mixed layer, but made excursions to 
cooler waters below the thermocline, potentially for benthic foraging 
(Dewar et al., 2004; Weng et al., 2007b). YOY white sharks seemed to 
use the upper thermocline, whereas older juvenile white sharks made 
deeper dives to cooler waters, indicating an expansion in 
thermoregulatory ability

[[Page 40119]]

and thermal tolerance as they grow older (Dewar et al., 2004; Weng et 
al., 2007b). The potential for climate change to increase SSTs and 
deepen the thermocline in the California Current System (King et al., 
2011) may expand foraging habitat and opportunities for young NEP white 
sharks. However, climate-related changes in the distribution of prey 
resources could also result in potential mismatches between predator 
and prey distributions (Hazen et al., 2012).
    The model predictions in Hazen et al. (2012) represent only one 
analysis of how climate change may affect the NEP white shark 
population and do not account for factors such as species interactions, 
food web dynamics, and fine-scale habitat use patterns that need to be 
considered to more comprehensively assess the effects of climate change 
on this ecosystem. The complexity of ecosystem processes and 
interactions complicate the interpretation of modeled climate change 
predictions and the potential impacts on populations such as the NEP 
white shark population. Thus, the potential impacts from climate change 
on the NEP white shark population and its habitat are highly uncertain, 
but the diverse diet and broad thermal tolerance of white sharks 
suggest the population has the capability to adapt to some level of 
climate-related SST change. The BRT also noted that the potential 
impacts of global warming and climate change on NEP white sharks are 
speculative at this time (Dewar et al., 2013).

Analysis of the Present or Threatened Destruction, Modification, or 
Curtailment of the Habitat or Range

    Habitat used by the NEP white shark population has been modified by 
the threats identified and discussed in this section. However, 
consistent with the BRT's assessment of threats (Dewar et al., 2013), 
we do not find evidence indicating that the impacts of pollution, 
depletion of prey species, ocean acidification, or climate change are a 
significant threat to the NEP white shark population. Although legacy 
pollutants remain in the SCB, pollutant inputs to this area have 
decreased since the 1970s as a result of improved discharge management 
(Raco-Rands, 1999 as cited in Schiff et al., 2000). White shark prey 
resources have substantially increased in abundance over the last 
several decades due to protections for marine mammals and improved 
fisheries management (Dewar et al., 2013). The effects of ocean 
acidification and climate change now and in the foreseeable future 
remain highly uncertain, but the best available information indicates 
that habitat used by the NEP white shark population is not likely to be 
substantially impacted or that the white shark population will be able 
to compensate for any habitat changes. Overall, the best available 
information suggests that identified threats related to the 
destruction, modification or curtailment of white shark habitat in NEP 
are not contributing to increasing the population's risk of extinction 
now or in the foreseeable future.

B. Overutilization for Commercial, Recreational, Scientific or 
Educational Purposes

    Potential threats to the NEP white shark population from 
overutilization for commercial, recreational, scientific or educational 
purposes include bycatch in a range of fisheries, international trade, 
ecotourism and scientific research. Each of these potential threats is 
discussed in the following sections.

High Seas Driftnet Fisheries

    As part of its threats evaluation, the BRT considered historical 
interactions between high seas driftnet fisheries and white sharks 
(Dewar et al., 2013). From the 1970s to the early 1990s there were 
large scale drift gillnet fisheries in the North Pacific Ocean 
targeting salmon, flying squid, tuna and billfish that had significant 
amounts of shark bycatch. The salmon fishery was located west of 
180[deg]W and is not likely to have interacted with white sharks from 
the NEP population. The areas used by the fisheries targeting flying 
squid, tuna and billfish were centered farther west and only overlapped 
with a small portion of the pelagic habitat used by NEP white sharks 
around the Hawaiian Islands, primarily west of the OFA area (Dewar et 
al., 2013). Catch of white sharks was reported in both the flying squid 
and large mesh drift gill net fisheries targeting tuna and billfish, 
but the available data are scarce and it is uncertain what population 
of white sharks was impacted by the fisheries (Dewar et al., 2013). 
Because of concerns about the bycatch of many species, including 
sharks, the high seas drift net fisheries were phased out in 1992 
following a United Nations resolution banning their use. It is 
uncertain whether any unregulated driftnet fishing occurs in the NEP; 
however, a survey of NMFS personnel involved in international affairs 
and Illegal, Unreported and Unregulated (IUU) fishing did not yield any 
information indicating these fisheries continue to operate in waters 
east of the Hawaiian Islands (Dewar et al., 2013).

Hawaii Long-Line Fisheries

    Based on the best available information, there is limited 
interaction between long line fisheries based in the Hawaiian Islands 
and white sharks. Observer data for the shallow set swordfish fishery 
based in Hawaii includes seven records of white sharks captured from 
1997-2008. The records were not verifiable (i.e., no photographs, etc., 
were taken) and were considered suspect by NMFS personnel familiar with 
the observer database (Dewar et al., 2013).

U.S. West Coast Commercial Fisheries

    Previous reports have described white shark bycatch in California 
fisheries (Klimley, 1985; Lowe et al., 2012). Data compiled for these 
studies from logbook records, landing receipts, fishery observer 
reports and scientific research studies indicate that historically most 
white sharks have been caught in gillnet fisheries. In general, most of 
the white shark bycatch in California gillnet fisheries occurred in 
southern California and consisted of YOY and juvenile sharks; however, 
both juveniles and adults were historically caught north of Point 
Conception when set and drift gillnet fisheries more commonly operated 
in those areas. Based on these studies, catches of white sharks were 
sporadic throughout the 1970s, followed by an increase in the 1980s as 
the small and large mesh net fisheries expanded. White shark catches 
subsequently decreased, reaching a low in 1994 when white sharks were 
protected by the State of California and gill and trammel nets were 
banned within 3 nmi of the mainland and 1 nmi of the Channel Islands 
(Lowe et al., 2012).
    As part of its threats evaluation and risk assessment, the BRT 
compiled and analyzed U.S. gillnet fisheries catch and effort data for 
white sharks from several sources including logbooks, Pacific Fisheries 
Information Network landing records, fishery observer records, and the 
Monterey Bay Aquarium scientific white shark collection program (Dewar 
et al., 2013). Based on this analysis, most reported catches of white 
sharks were in the coastal set gillnet and large-mesh drift net 
fisheries prior to the mid-1990s. Reported catch numbers peaked during 
the mid-1980s and declined steadily thereafter as fishing effort 
decreased as a result of changes in fishing regulations and 
implementation of the 1994 near-shore set gillnet ban in California. 
The set gillnet fisheries operated primarily over the continental shelf 
and as a consequence of the 1994 ban they were restricted to just a few 
areas in the SCB including the Ventura

[[Page 40120]]

Flats, Channel Islands, Huntington Flats, and Oceanside where the 
continental shelf extends beyond the 3 nmi closure area. A time-area 
closure was implemented for the large mesh drift gillnet fleet in 2001 
that essentially eliminated this fishery from near-shore waters north 
of Morro Bay. Since 1999 only one white shark capture has been reported 
in the drift gillnet fishery. Most catch of white sharks now occurs in 
the set gillnet fishery which has reported increasing catches since the 
mid-2000s. Lowe et al., (2012) suggested that the increased number of 
YOY and juvenile white sharks caught since the mid-2000s could be the 
result of past reductions in fishery mortality that led to an 
increasing white shark population and associated YOY and juvenile 
production. The BRT found that CPUE of white sharks in gillnet 
fisheries was substantially higher over the period from 2002-2011 
compared with the period from 1990-2001 (Dewar et al., 2013) and noted 
that these findings are consistent with the increase in white shark 
abundance suggested by Lowe et al. (2012).

Recreational Fisheries

    Interactions between recreational fisheries off California and 
white sharks are known to occur, but there is relatively little 
documentation of such interactions. From 1980-2011, 7 white sharks were 
reported in logbooks from commercial passenger fishing vessels and 1 
white shark was reported caught by a private angler (CDFW, 2013). White 
sharks are occasionally caught off public fishing piers in southern 
California and two citations were issued by CDFW for illegal take of 
juvenile white sharks off piers in 2012 (CDFW, 2013).

Mexican Fisheries

    As part of its threats evaluation, the BRT reviewed available 
information on the catch of white sharks in Mexico including recently 
published information and unpublished information from researchers in 
Baja California (Dewar et al., 2013). Information on white shark 
bycatch from the Pacific coast of the Baja Peninsula and from the Gulf 
of California has been reported by several researchers (Galv[aacute]n-
Maga[ntilde]a et al. 2010; Castro, 2012; Santana-Morales et al 2012).
    Santana-Morales et al. (2012) summarized the results of white shark 
catch records from various fisheries for the period from 1999-2010 and 
found that 80 percent of the white sharks taken were YOY and that most 
were caught in Sebasti[aacute]n Vizca[iacute]no Bay during the summer. 
More recent efforts to quantify catch of white sharks have been 
conducted by researchers who have worked directly with local fish 
distributors operating in Sebasti[aacute]n Vizca[iacute]no Bay (Sosa-
Nishizaki, personal communication cited in Dewar et al., 2013). 
Although there are potential problems associated with the 
identification of white sharks in Baja California because of the way 
shark species are processed, this approach allowed the researchers to 
work directly with the point of contact for all fishermen in the area. 
According to Sosa-Nishizaki (personal communication cited in Dewar et 
al., 2013), distributors reported receiving 186 white sharks in 2011 
from fishermen operating in Baja California, with the vast majority 
having been caught in Sebasti[aacute]n Vizca[iacute]no Bay. To reduce 
impacts on sharks, the Mexican government prohibited shark fishing 
along the Pacific coast of Mexico from June 1--July 31 in 2012, and, 
beginning in 2013, has expanded the closure to include the month of 
May. The reported catch of white sharks in 2012 was substantially 
reduced by this action and further catch reductions are possible with 
the expanded closure. White sharks are also caught along the Pacific 
coast of the southern portion of the Baja California peninsula, but 
that information has not been quantified.
    White sharks are known to be caught on fishing gear in the Gulf of 
California, but incidental catch records are not well quantified. 
Galv[aacute]n-Maga[ntilde]a et al. (2010) reported that small numbers 
of adult, subadult and juvenile white sharks were caught in the Gulf of 
California based on records from 1964 to 2010. To date there is only 
one record of a YOY white shark being captured in the Gulf of 
California (Sosa-Nishizaki, personal communication cited in Dewar et 
al., 2013), although large females are documented to come into this 
area.
    As previously discussed (see Fisheries Risk Assessment Modeling 
section), the BRT conducted population modeling using white shark catch 
and mortality data to assess the impact of mortality from U.S. and 
Mexican fisheries on white shark population growth rates and changes in 
adult female population abundance over time (Dewar et al., 2013). Based 
on the results of this modeling analysis, the BRT concluded that the 
NEP white shark population is at a very low to low risk from the U.S. 
and Mexican fisheries if the population includes at least 200 adult 
females as the BRT believes is likely to be the case (Dewar et al., 
2013).

International Trade

    International trade of white shark fins, jaws, and teeth for 
consumption or as trophies or curios has been identified as a threat to 
white shark populations worldwide (CITES, 2004; Clarke et al., 2004; 
Fowler et al., 2005; Shivji et al., 2006) and the high value of these 
white shark products may act as an incentive for poaching and illegal 
trade (Compagno, 2001). The extent of international trade in white 
shark products is difficult to determine (Clarke et al., 2004); 
however, genetic analysis of confiscated white shark fins in a law 
enforcement case on the U.S. East coast confirmed the illegal trade of 
white shark fins (Shivji et al., 2005). This case provides evidence for 
illegal trade impacts on the global population of white sharks, and 
therefore, it is possible that white sharks from the NEP may be part of 
this trade. However, there is no information currently available to 
assess whether white sharks from the NEP are part of this illegal trade 
and there are no documented cases of illegal trade in white shark parts 
in California (CDFW, 2013).

Ecotourism Activities

    White shark ecotourism activities, including cage diving, shark 
watching operations, and filming, are known to be conducted off the 
Farallon Islands in central California and at Guadalupe Island off Baja 
California (CITES, 2004; DOF, 2004 and 2006; Domeier and Nasby-Lucas, 
2006; NOAA, 2008). While ecotourism provides benefits to white sharks 
as a non-consumptive use that raises public awareness of the species, 
there is the potential for these activities to harass white sharks and 
alter their natural behaviors (CITES, 2004; Fowler et al., 2005; 
Laroche et al., 2007; NOAA, 2008). White sharks are believed to hunt by 
swimming at depth so that they can spot pinnipeds in the water above 
them without being seen; however, ecotourism activities often try to 
attract white sharks to the surface by setting out bait or decoys and 
keep them at the surface for as long as possible (Fowler et al., 2005; 
Laroche et al., 2007). Frequent or cumulative encounters with humans 
and vessels due to these activities could result in altered behavior 
(e.g., conditioning of sharks to associate vessels with food rewards), 
changes to feeding strategies (e.g., increased time spent at the 
surface versus swimming at depth), and increased or decreased residency 
times in the area (Laroche et al., 2007). Laroche et al. (2007) 
conducted an experimental study to examine the effects of chumming 
activities on white

[[Page 40121]]

shark behavior in South Africa and observed only minor, short-term 
changes in behavior; however, the study was limited in scope and may 
not apply to all ecotourism operations.
    Regulations on ecotourism activities have been adopted in some 
areas to address the potential impacts of these activities on white 
sharks. In 2002, the State of Hawaii banned shark feeding in state 
marine waters due to concerns that such activities were altering the 
natural behavior of sharks as well as altering the environment and 
potentially increasing the risk of shark attacks (Fowler et al., 2005). 
In 2008, the Gulf of the Farallones National Marine Sanctuary adopted 
regulations to prohibit attracting white sharks within the Sanctuary's 
waters and to prohibit approaching within 50 m of any sharks in waters 
within 2 nmi of the Farallon Islands. These regulations are meant to 
minimize the disturbance of white sharks and interference with their 
natural behaviors from ecotourism activities (primarily cage diving) 
and scientific research activities conducted around the Farallon 
Islands (NOAA, 2008). A similar prohibition on attracting white sharks 
was adopted for the Monterey Bay National Marine Sanctuary, although 
cage diving operations are not known to occur in waters off Monterey 
Bay (NOAA, 2008).
    Commercial cage diving operations began off Guadalupe Island in 
2002 (Domeier and Nasby-Lucas, 2006) and visit the same sites each year 
(Sosa-Nishizaki et al., 2012). According to Sosa-Nishizaki (personal 
communication to Susan Wang, NMFS, 2013), Mexico limits commercial cage 
diving to 6 vessels at 3 locations and requires all vessels to have 
permits, licenses, and adhere to a code of conduct designed to protect 
white sharks at the island. The code of conduct prohibits fishing for 
white sharks, approaching within 50m of white sharks foraging on marine 
mammals, the use of decoys to attract white sharks, and the feeding or 
touching of white sharks. The code of conduct does allow use of bait 
with several restrictions.
    Overall, ecotourism activities have the potential to disturb and 
alter the natural behavior of NEP white sharks, but the potential 
impacts of such activities are poorly understood and at least one study 
suggests that the impacts may be minor. Regulations currently exist for 
waters around the Hawaiian Islands, Farallon Islands and Guadalupe 
Island that likely minimize disturbance of white sharks from ecotourism 
activities.

State-Permitted Scientific Research Activities in California

    In California, the take of white sharks is prohibited except as 
permitted for scientific or educational purposes. Reports submitted by 
CDFW permit holders from 2007 through 2011 indicate that a total of 107 
white sharks were tagged and released alive and that six white sharks 
were retained for live display (CDFW, 2013). Thus, a relatively large 
number of white sharks have been captured and handled as part of state-
permitted research activities in California since 2007.
    Effective March 1, 2013, the California Fish and Game Commission 
designated white sharks as a candidate species for listing under the 
California Endangered Species Act (CESA), thereby initiating a formal 
review of the species' status. As a candidate species, white sharks in 
California are afforded the full legal protection of a listed species 
under CESA and their take is prohibited except as expressly permitted 
under CESA. On March 1, 2013, the State revoked all previously issued 
scientific collection permits and notified researchers that they must 
obtain new permits under CESA in order to continue their scientific 
research and collection activities. The CDFW is currently reviewing 
research reports and working with former permit holders to evaluate 
their past research activities in order to assess the overall effects 
of past research on white sharks in California waters and the extent of 
targeted fishing for white sharks in association with this research 
(CDFW, 2013).

Analysis of Overutilization for Commercial, Recreational, Scientific, 
or Educational Purposes

    High seas drift net fisheries may have had historical impacts on 
the NEP white shark population, but those impacts are likely to have 
been limited because those fisheries did not overlap extensively with 
the offshore habitat used by the population. Those fisheries were 
banned in the early 1990s and we have no current information indicating 
that there are illegal high seas fisheries in the offshore areas used 
by the NEP white shark population. Historically and at present, various 
types of gillnet fisheries along the U.S west coast, primarily in 
southern California, have taken white sharks. However, white shark 
catch and mortality associated with these fisheries have declined 
substantially since the late 1980s and early 1990s as fishing effort 
declined as a result of protections implemented by the State of 
California (e.g., State protection of white sharks, changes in fishing 
regulations, and a ban on gillnet fishing in much of southern 
California). Recent evidence indicates that CPUE of white sharks in 
southern California has actually increased in recent years despite 
reduced fishing effort, suggesting that the white shark population may 
be increasing (Dewar et al., 2013). Various artisanal fisheries in 
Mexico also take white sharks, primarily along the northern coast of 
Baja California which is part of the NEP white shark's nursery habitat 
for YOY and juvenile sharks. Recent information suggests that this area 
currently has the highest level of white shark catch and mortality, but 
reported catches were substantially reduced after Mexico implemented a 
seasonal (June and July) ban on shark fishing on the Pacific coast of 
Mexico in 2012. This ban was expanded to include the month of May 
beginning in 2013 and thus white shark catch levels may be reduced even 
more in the future. The BRT conducted extinction risk modeling to 
evaluate the present and future risks of U.S. and Mexican fishery 
mortality on the NEP white shark population and found the estimated 
mortality levels are sustainable and that risks to the population are 
low to very low (Dewar et al., 2013). Other activities, such as 
international trade in white sharks, ecotourism and scientific 
collection of white sharks, most likely have minimal impacts on the NEP 
white shark population. Overall, the best available information 
indicates that these threats are not contributing substantially to the 
population's risk of extinction now or in the foreseeable future.

C. Disease and Predation

    Limited information is available for white sharks regarding disease 
and predation. Although common parasites such as large copepods and 
intestinal cestodes have been found in white sharks, it is not known 
how these parasites affect individual animals or populations (Compagno, 
2001). Young white sharks caught off the coast of southern California 
have been found to have high concentrations of mercury and 
organochlorines (DDT and PCBs) in their liver and muscle tissues, but 
the potential impacts on the health of white sharks are unknown (Mull 
et al., 2012). Exposure to contaminants such as DDT and PCBs has been 
linked to increased incidence of diseases in certain fish species 
within the SCB (Mearns and Sherwood, 1977; Cross, 1988; Stull, 1995; 
Allen et al., 1998; all cited in Schiff et al., 2000), but no such 
linkages have yet been studied or documented in white sharks.

[[Page 40122]]

    Little is known about predation on white sharks by other species; 
however, given the species' size and status as a top-level predator it 
is likely that predation on any life history stage is relatively low 
(Dewar et al., 2013). The BRT concluded that the most likely predators 
of white sharks are killer whales and other larger sharks (Dewar et 
al., 2013). There is one confirmed predation event on a white shark 
indicating that at least smaller white sharks may be vulnerable to 
predation by large predatory marine mammals. In 1997, fishermen and 
researchers observed an adult transient killer whale kill and partially 
ingest an intermediate-sized white shark (likely a subadult) near the 
Southeast Farallon Islands (Pyle et al., 1999). Pyle et al. (1999) 
suggested that the white shark killed in this event was likely 
attracted to the surface by a recently killed pinniped carcass because 
white sharks at this site typically are near the bottom rather than the 
surface (Goldman et al., 1996, cited in Pyle et al., 1999). In November 
2000 another predation event was observed around the Farallon Islands 
involving a killer whale and a ``large prey item'' that could have been 
a white shark (Pyle and Anderson, unpublished observations cited in 
Weng et al., 2007). Other predation events such as these may occur, but 
are not well documented in the literature most likely because of their 
rarity. Compagno (2001) suggested that large pinnipeds and other large 
shark species may kill or injure white sharks, but except for 
occasional seal bite marks on sharks there is little evidence of such 
behavior.

Analysis of Disease and Predation

    The best available information indicates that the effects of 
disease, predation and competition on the NEP white shark population 
are limited. The BRT concluded that disease and predation are low-level 
threats to the population (Dewar et al., 2013). Overall, there is no 
information indicating that these factors are contributing to 
increasing the population's risk of extinction or that they are likely 
to do so in the foreseeable future.

D. The Inadequacy of Existing Regulatory Mechanisms

    Existing regulatory mechanisms include Federal, state, and 
international regulations and management measures. Below, we describe 
the current domestic and international regulatory mechanisms that 
affect the NEP white shark population, followed by an evaluation of 
their adequacy.

U.S. Federal Regulations

    Federal regulations that provide protection for white sharks in the 
NEP include white shark-specific regulations under the West Coast 
Highly Migratory Species Fishery Management Plan (HMS FMP) and in west 
coast National Marine Sanctuaries, as well as general shark protections 
under the Shark Finning Prohibition Act of 2000 and the Shark 
Conservation Act of 2010.
    Under the West Coast HMS FMP white sharks are a prohibited species, 
meaning that their retention is prohibited and they must be released 
immediately if caught (PFMC, 2011; NMFS, 2011). This prohibition 
applies to all U.S. vessels that fish for highly migratory species 
using authorized gear (e.g., large mesh drift gillnet, deep-set 
longline, tuna troll and purse seine) within the U.S. exclusive 
economic zone and the state waters of California, Oregon and 
Washington, as well as U.S. vessels fishing for highly migratory 
species on the high seas that land their fish in California, Oregon or 
Washington (PFMC, 2011).
    The large mesh drift gillnet fishery for swordfish and thresher 
shark is one of the federally-managed fisheries authorized under the 
West Coast HMS FMP. Based on logbook records, bycatch of white sharks 
in this fishery has steadily declined since the early 1980s with only 
one individual reported caught since 2000 (Dewar et al., 2013). This 
reduction in bycatch is most likely due to changes in the management of 
the fishery over time, including a delay in the start of the fishing 
season, gear changes, and a time/area closure that largely eliminated 
the fishery from areas north of Morro Bay (Dewar et al., 2013). Prior 
to adoption of the West Coast HMS FMP, the State of California was 
responsible for the management of the large mesh drift gillnet fishery 
and implemented a series of restrictions which provided additional 
protections for white sharks. All of these regulations have been 
incorporated into the FMP for this fishery.
    Other measures that have been implemented to reduce the bycatch of 
marine mammals and sea turtles in the drift gillnet fishery are also 
likely to have reduced interactions with white sharks in the NEP. For 
example, the Pacific Offshore Cetacean Take Reduction Plan requires the 
use of extenders to lower drift gillnets in the water column to avoid 
cetaceans swimming near the surface, which likely reduces potential 
interactions with small white sharks that typically spend the majority 
of their time near the surface of the water column (Dewar et al., 
2013). Similarly, the Pacific Leatherback Conservation Area (PLCA), 
which prohibits use of drift gillnet gear over a large area off central 
California from August 15 to November 15 and over a large portion of 
the SCB from June 1 to August 31 during declared El Ni[ntilde]o events 
to protect loggerhead sea turtles, is likely to provide some level of 
protection to adult and subadult white sharks in these areas and at 
these times.
    The Gulf of the Farallones National Marine Sanctuary (GFNMS) and 
Monterey Bay National Marine Sanctuary (MBNMS) have prohibited efforts 
to attract white sharks. The GFNMS also prohibits vessels from 
approaching within 50 m of any white shark anywhere within 2 nmi around 
the Farallon Islands. The Sanctuaries adopted these prohibitions 
primarily to regulate adventure tourism activities (e.g., commercial 
white shark viewing enterprises such as cage diving operations), 
filming, and scientific research activities that can disturb white 
sharks and interrupt their natural feeding and daily activities (NOAA, 
2008). Although there is no prohibition on approaching white sharks 
within the GFNMS outside of the 2 nmi boundary around the islands, the 
area inside this boundary is where white sharks are most prevalent when 
they are feeding, and thus, interactions with white sharks are reduced 
by this action (NOAA, 2008). The Sanctuaries have issued permits to 
allow some white shark approach or attraction activities for legitimate 
research or educational purposes. These permitted activities are 
reviewed on a case-by-case basis and are subject to reporting 
requirements and other terms and conditions as deemed necessary to 
protect Sanctuary resources.
    The Shark Finning Prohibition Act of 2000 amended the Magnuson-
Stevens Fishery Conservation and Management Act (MSA) to prohibit the 
practice of shark finning (i.e., removing the fins of a shark, 
including the tail, and discarding the carcass of the shark at sea) by 
any person under U.S. jurisdiction. This Act also amended the MSA to 
prohibit having custody, control, or possession of shark fins aboard a 
fishing vessel without the corresponding carcass or landing shark fins 
without the corresponding carcass; however, a provision does permit 
some level of shark finning to occur. In 2011, the Shark Conservation 
Act of 2010 was signed into law to further strengthen the prohibitions 
on shark finning under the MSA as well as under the High Seas Driftnet 
Fishing Moratorium Protection Act. These amendments to the MSA clarify 
that it is illegal for all vessels to

[[Page 40123]]

have custody of, transfer, or land a shark fin unless it is naturally 
attached to the corresponding shark carcass, but it does allow some 
retention of shark fins after the sharks have been landed (NMFS, 2011). 
The 2010 Act also amended the High Seas Driftnet Act to include shark 
conservation measures, including measures to prohibit shark finning at 
sea in international agreements negotiated by the United States. (NMFS, 
2011). These provisions under the MSA and the High Seas Driftnet Act 
provide some protections for white sharks in domestic and international 
waters by regulating shark finning activities.

State Regulations

    State fisheries regulations vary by state and by fishery from 
general shark management measures to specific protections for white 
sharks. Below is an overview of state regulations that may affect the 
NEP white shark population, but with a focus on California regulations, 
as the majority of fishery interactions with white sharks along the 
west coast of the U.S. occur offshore California.
    In 1994, white sharks received special protected status in the 
State of California by the addition of Sections 5517 and 8599 to the 
State's Fish and Game Code (CDFW, 2013). Section 5517 prohibited the 
take of white sharks, except by special permit from the CDFW. Section 
8599 prohibited commercial take of white sharks except for scientific 
and educational purposes under State-issued scientific collection 
permits, but did allow for the incidental take of white sharks by round 
haul or gillnet and the sale of any live-landed white sharks for 
scientific or live display purposes under scientific collection 
permits. On March 1, 2013, the State of California accepted a petition 
to list white sharks under the CESA. This action conferred candidate 
species status to white sharks while the State undertakes a year-long 
status review of the NEP population. As a candidate species, white 
sharks have full legal protection under CESA, which includes a 
prohibition on the take of white sharks in fisheries and for scientific 
or educational purposes. While a candidate for listing under CESA, the 
take of white sharks is only allowed in fisheries or for scientific 
purposes pursuant to a special CESA permit and to date no such permits 
have been issued by CDFW. It is uncertain what the outcome of the 
status review will be or whether the State will list white sharks under 
CESA, but white sharks will continue to have legal protection as a 
candidate species until the State renders its listing decision.
    Changes to commercial fishing regulations in California since the 
1980s have provided additional protection for white sharks and reduced 
fishery interactions and bycatch. The majority of reported captures of 
white sharks off California have occurred in coastal gill net fisheries 
(Lowe et al., 2012). Since 1994, gillnet use has been banned in the 
Marine Resources Protection Zone in southern California which includes 
all state waters south of Point Arguello (i.e. areas inside 3 nmi from 
the mainland coast) and waters less than 70 fathoms (fm) deep or within 
1 nmi of the California Channel Islands. Since 2000, gillnet use has 
also been prohibited in waters shallower than 60 fm along the 
California coast between Point Arguello and Point Reyes, which has 
effectively restricted gill net use to a few limited areas in southern 
California. These actions have served to reduce or eliminate gill net 
fishing effort and thereby reduce interactions with white sharks in 
California. Seasonal closures and the timing of gill net fisheries that 
continue to exist in southern California for white seabass and 
California halibut are also likely to reduce fishery interactions with 
white sharks (CDFW, 2013). As a result of these area and time closures 
in southern California, current gill net fishing effort overlaps with 
less than a third of the available YOY white shark habitat based on 
satellite tagging studies (Chris Lowe, California State University, 
Long Beach, personal communication cited in Dewar et al., 2013).
    In Oregon, the take of white sharks is prohibited in sport 
fisheries and they must be released immediately and unharmed if taken. 
In contrast, the take of white sharks is not specifically prohibited or 
regulated in commercial fisheries. Washington and Alaska do not have 
fishing regulations that specifically address white sharks, but include 
white sharks in general bottomfish or shark categories for which 
fishing is regulated. Hawaii does not have fishing regulations that 
specifically address white sharks, but prohibits the feeding of sharks 
within the State's marine waters. California, Oregon, Washington, and 
Hawaii have all adopted shark finning prohibitions making it unlawful 
to possess, sell, offer for sale, trade, or distribute shark fins, and 
this may provide some protection for white sharks in the NEP.

International Authorities

    Canada and Mexico, the two other nations within the range of the 
NEP white shark population, have each adopted regulations that directly 
and/or indirectly provide protections for white sharks. In addition, 
the status of the global population of white sharks (including the NEP 
population) has been assessed under the Convention on International 
Trade in Endangered Species of Wild Fauna and Flora (CITES), the 
International Union for Conservation of Nature (IUCN), and the 
Convention on the Conservation of Migratory Species of Wild Animals 
(CMS). Several international authorities have also addressed 
protections applicable to all shark species that may provide some 
protection for the NEP white shark population. We briefly describe 
these protections below.
    In Canada, the Atlantic population of white sharks was listed as 
endangered by the Committee on the Status of Endangered Wildlife in 
Canada (COSEWIC) in 2006 and under the Species At Risk Act (SARA) in 
2011 (Environment Canada, 2011; SARA Annual Report for 2011; https://www.sararegistry.gc.ca/virtual_sara/files/reports/LEP-SARA_2011_eng.pdf), whereas the Pacific population of white sharks was listed as 
``Data Deficient'' by COSEWIC in 2006 (COSEWIC, 2006) and is currently 
not listed under SARA. Data deficient is a category that applies when 
the available information is insufficient to resolve a species' 
eligibility for assessment or to permit an assessment of the species' 
risk of extinction. White sharks in the NEP were listed as data 
deficient primarily due to their rarity in Canadian waters and the lack 
of abundance trend information for Pacific Canadian waters and adjacent 
U.S. waters (COSEWIC, 2006). Although Canada does not have any Federal 
or provincial laws that explicitly protect white sharks on the Pacific 
Coast, hook-and-line fisheries on Canada's Pacific Coast are prohibited 
from keeping any species of shark except for dogfish (COSEWIC, 2006), 
and this likely provides some protection for the NEP white shark 
population.
    Mexico listed white sharks as a threatened species in 2001 (NORM-
059-ECOL-2001) based on a review of available literature and data 
analysis, but this action did not provide any specific protections to 
the species. Since then, Mexico has adopted regulations for the 
protection of white sharks and sharks in general. In 2007, Mexico 
published an Official Norm (DOF, 2007; NOM-029-PESC 2006) on 
responsible shark and ray fishing that prohibits the catch and 
retention of white sharks, whether alive or dead, whole or in part. The 
Official Norm also prohibits the landing of shark fins unless the shark 
bodies are also on board fishing vessels, prohibits any increases in 
the total allowable fishing effort for sharks and

[[Page 40124]]

rays, and establishes various gear and area restrictions for fisheries 
targeting sharks and rays (DOF, 2007; Barreira, 2008). Despite the 
prohibition on catch and retention, studies have documented the catch 
and retention of white sharks in fisheries off Baja California 
(Cartamil et al., 2011; Santana-Morales et al., 2012). In 2012, Mexico 
adopted a seasonal ban on fishing for all shark species in national 
waters of the Pacific Ocean from June through July beginning in 2012 
and between May through July each subsequent year (DOF, 2012). This ban 
is expected to provide increased protection for YOY and juvenile white 
sharks by reducing their interactions with coastal gillnet fisheries. 
Based on limited information, for example, this seasonal ban reduced 
the documented catch and retention of YOY and juveniles by 
approximately 50 percent in 2012 (Sosa-Nishizaki, personal 
communication cited in Dewar et al., 2013), although it is possible 
that not all white shark catches were reported. Expansion of the shark 
fishing ban to include the month of May starting in 2013 is expected to 
further reduce impacts to white sharks in these coastal gillnet 
fisheries, but more effective monitoring of the fisheries and 
enforcement of this ban are needed to ensure that impact reductions are 
realized.
    Other than the white shark catch information that was considered by 
the BRT in its fisheries risk assessment modeling (Dewar et al., 2013), 
there do not appear to be any estimates of total white shark bycatch in 
Mexico. Improved collection and reporting of white shark catch data are 
needed to better evaluate impacts to the population and the 
effectiveness of Mexican fisheries regulations for white sharks. 
Regulation and enforcement of gillnet fisheries that interact with and 
take white sharks in Mexico is important because coastal waters of 
northern Baja California are part of the nursery area for the NEP white 
shark population and some portion of the YOY and juvenile component of 
the population uses this habitat (Weng et al., 2007; Chris Lowe, 
California State University, Long Beach, personal communication, 2012; 
Dewar et al., 2013).
    Under CITES, species may be listed in three appendices: Appendix I 
(species threatened with extinction), Appendix II (species not 
necessarily threatened with extinction, but that might become so unless 
trade is subject to regulation), or Appendix III (species protected in 
at least one country that has asked for assistance from other Parties 
to CITES for help in controlling international trade). CITES requires 
countries to regulate and monitor trade in products from species listed 
in the appendices using a permitting system that has different 
requirements depending upon the Appendix in which a species is listed. 
In 2004, white sharks were listed under Appendix II of CITES, meaning 
that international trade in white shark specimens must be authorized by 
export permits or re-export certificates. Granting of these permits or 
certificates is based on an evaluation of whether certain conditions 
are being met, including a determination that trade will not be 
detrimental to the species' survival in the wild.
    The IUCN Red List is an assessment of a species' extinction risk on 
a worldwide basis. Listing a species on the IUCN Red List does not 
provide any regulatory protections for the species, but serves as an 
evaluation of the species' status. The global population of white shark 
species was assessed and categorized as ``vulnerable'' in 1996, 2000 
and 2009, meaning that the species was considered to be facing a high 
risk of extinction in the wild (IUCN, 2001). The criteria for assessing 
whether a species should be listed on the IUCN Red List are different 
than the standards for making a determination that a species warrants 
listing as threatened or endangered under the ESA, and hence, the 
``vulnerable'' assessment for the global white shark species does not 
directly inform our analysis of extinction risk for the NEP white shark 
population.
    The Convention on the Conservation of Migratory Species of Wild 
Animals (CMS or Bonn Convention) is an intergovernmental treaty under 
the United Nations Environment Programme. Migratory species may be 
listed under Appendix I (species categorized as being in danger of 
extinction throughout all or a significant portion of their range) or 
Appendix II (species that need or would significantly benefit from 
international cooperation) of the CMS. The CMS supports protection and 
conservation of the species listed under the appendices through legally 
binding treaties (called Agreements) and non-legally binding Memoranda 
of Understanding (MOU). The United States, Mexico, and Canada are not 
Parties to the CMS, but the United States is a signatory to some MOUs 
under the CMS. In 2002, the global population of white sharks was 
listed under both Appendix I and II of the CMS, and in 2010 the CMS 
adopted a non-binding MOU on the Conservation of Migratory Sharks to 
improve the conservation status of white sharks and other shark species 
listed under the appendices. This MOU, to which the United States is a 
signatory, does not provide regulatory protections for these shark 
species, but encourages Signatories to adopt and implement measures to 
protect the species and its habitat. Measures include prohibitions on 
shark finning activities, prohibitions on take of the species, and 
implementation of National Plans of Action for sharks, as called for 
under the United Nations Food and Agriculture Organization's (FAO) 1999 
International Plan of Action for sharks.
    In 1999, the FAO adopted the International Plan of Action for the 
Conservation and Management of Sharks (IPOA-Sharks) to ensure the 
conservation and management of sharks and their long-term sustainable 
use (FAO, 1999). Under the IPOA-Sharks, members and non-members of the 
FAO are encouraged to develop national plans of action to address shark 
conservation and management needs, including sustainable management and 
monitoring of shark catches in fisheries; minimization of incidental 
catch, waste, and discards; and assessments of threats to shark 
populations (FAO, 1999). The United States, Mexico and Canada, as well 
as several other nations, have each adopted and implemented a National 
Plan of Action for the Conservation and Management of Sharks under the 
IPOA-Sharks. These plans may provide some conservation benefit to the 
NEP white shark population by improving the management of shark 
fisheries and conservation of shark species in these nations; however, 
the effectiveness of such plans has not yet been demonstrated (Lack and 
Sant, 2011).
    International efforts have also focused on minimizing waste and 
discards through the regulation or prohibition of shark finning 
activities. Two regional entities in the Pacific Ocean, the Western and 
Central Pacific Fisheries Commission (WCPFC) and the Inter-American 
Tropical Tuna Commission (IATTC), have adopted resolutions to regulate 
shark fishing and shark finning activities among member and cooperating 
non-member nations (including the United States, Mexico and Canada). 
The WCPFC and IATTC resolutions state that members and cooperating non-
member nations shall require full utilization of retained catches of 
sharks and shall prohibit vessels from having on board shark fins that 
total more than 5 percent of the weight of sharks on board (IATTC, 
2005; WCPFC, 2010). The resolutions also call on member and cooperating 
non-member nations to encourage the live release of sharks in their 
fisheries when they are caught incidentally and not

[[Page 40125]]

used for food. The WCPFC Convention Area encompasses waters around the 
Hawaiian Islands and the IATTC Convention Area encompasses offshore 
waters used by the NEP white shark population, including the OFA.

Analysis of Inadequacy of Existing Regulatory Mechanisms

    Protective efforts have been implemented under both U.S. Federal 
and state authorities since the early 1990s to reduce impacts on the 
NEP white shark population, including prohibitions on take of white 
shark in fisheries and more protective fishery regulations (e.g., time 
and area closures, etc.). These efforts have reduced fishing effort in 
areas used by white sharks, particularly in the SCB, and this has 
substantially reduced fishery impact on the NEP white shark population. 
We conclude that these regulatory measures provide adequate protection 
to the NEP white shark population from fishery impacts in U.S. waters 
and in State waters offshore California where the species is most 
abundant. However, protective efforts could be improved for white 
sharks in State waters offshore Oregon and Washington, and observer 
coverage of gillnet fisheries in California could be expanded to 
provide more information about white shark bycatch.
    White sharks are also protected in Mexico, and fishery regulations 
have been implemented since the early 2000s to reduce fishery impacts. 
Nevertheless, white sharks, primarily YOY and juveniles, continue to be 
caught and retained in gillnet fisheries along the coast of Baja 
California, primarily by fishermen operating from remote artisanal 
fishing camps. Enforcement of the existing regulations needs to be 
improved, but monitoring fishing activities in remote artisanal fishing 
camps is difficult. In addition to improved enforcement, additional 
monitoring of the fisheries is necessary as are efforts to educate the 
fishing community about shark species identification and shark 
conservation. A seasonal shark fishing ban recently adopted by Mexico 
resulted in a reduction in the reported catch of white sharks along the 
Baja California coast in 2012, but enforcement is necessary to ensure 
that fishermen comply with the ban and the ban needs to be evaluated 
over time to assess its long-term effectiveness in reducing impacts to 
white sharks.
    The recently-adopted prohibitions on attracting and approaching 
white sharks in the GFNMS and MBNMS provide a high level of protection 
for white sharks by reducing human interactions and the potential 
disruption of natural behaviors from activities such as cage diving 
operations, shark viewing operations, and scientific research. In 
waters off Guadalupe Island, where ecotourism operations have been 
conducted since the early 2000s, Mexico requires permits for commercial 
cage operations, limits the number of permits and the locations where 
permit holders can operate, and requires that permit holders adhere to 
a code of conduct designed to protect white sharks at the island. The 
code of conduct prohibits fishing for white sharks, approaching within 
50m of white sharks foraging on marine mammals, the use of decoys to 
attract white sharks, and the feeding or touching of white sharks.
    In 1994, California prohibited the take of white sharks except as 
permitted for scientific or educational purposes. Under these 
scientific collection permits, researchers often collaborated with 
fishermen to obtain white sharks incidentally caught in commercial 
fisheries for tagging and other studies. Because white sharks are now a 
candidate species for listing under the CESA, all scientific collection 
permits have been revoked and the CDFW is currently reviewing this 
program to evaluate the effects of state-permitted research activities 
on NEP white sharks. It is uncertain if and when permits will be issued 
under CESA and whether or not additional restrictions will be placed on 
permit holders.
    We conclude that existing Federal and State regulatory mechanisms 
provide adequate protection of the NEP white shark population. Federal 
and State regulations, particularly in California, have reduced impacts 
to white sharks from fisheries and other activities in nursery habitat 
and other areas where they aggregate and forage. However, regulatory 
mechanisms for fisheries in Mexico, primarily those related to 
monitoring, enforcement, and education of fishermen, need to be 
improved to ensure that existing regulations are implemented, to 
evaluate the effectiveness of existing regulations and to determine if 
additional regulations are needed. The BRT evaluated the impact of U.S. 
and Mexican fisheries on the NEP white shark population under the 
current regulatory regime and concluded the population is at a low to 
very low risk from these fisheries if the population includes at least 
200 adult females as seems most plausible (Dewar et al., 2013). 
Overall, the best available information indicates that existing 
regulatory mechanisms are adequate and that they are not contributing 
to increasing the population's risk of extinction now or in the 
foreseeable future.

E. Other Natural or Man-Made Factors Affecting the Population's 
Continued Existence

Natural Factors

    Because of concerns raised about the possible small size of the NEP 
white shark population, the BRT evaluated the population's 
vulnerability to the risks often associated with small populations 
(Dewar et al., 2013). These risks include increased difficulty finding 
mates, loss of genetic diversity, demographic stochasticity (variation 
in productivity), and stochastic and catastrophic events. The BRT 
generally found that the behavior and life history characteristics of 
white sharks are likely to mitigate these small population risks. For 
example, the offshore migratory behavior and aggregation of subadults 
and adults at coastal sites with pinniped colonies increases the 
probability that individuals will find mates for reproduction, even if 
the number of individuals in the population is relatively small. The 
BRT found that the NEP white shark population has a high level of 
genetic diversity based on a relatively high number of unique mtDNA 
haplotypes (Jorgensen et al., 2010) and suggested that giving birth to 
live young and the practice of multiple paternity increases the 
effective size of the population and contributes to maintaining this 
genetic diversity (Hoekert et al., 2002). Because white sharks give 
birth to large, live young, their survival is increased, which 
contributes to decreasing the population's vulnerability to demographic 
stochasticity. Finally, the BRT noted that several characteristics of 
the NEP white shark population indicate that NEP white sharks should be 
resilient to catastrophic and stochastic events, including their 
migratory behavior, the population's broad offshore distribution, and 
the large degree of spatial separation between life stages as well as 
between adult males and females. Overall, the BRT's analysis indicated 
that even if the NEP white shark population is relatively small, its 
size is not likely to contribute significantly to the population's risk 
of decline or extinction (Dewar et al., 2013).

Manmade Factors--Bioaccumulation of Contaminants

    The bioaccumulation of contaminants by white sharks in the SCB is a 
potential risk to the NEP white shark population. Life history factors, 
including a long life span, a high trophic position, and a large lipid-
rich liver, make white sharks susceptible to bioaccumulation (Mull et 
al., 2012). As described previously (see

[[Page 40126]]

Present or threatened destruction, modification, or curtailment of 
habitat or range), DDT and PCBs still exist in the SCB due to inputs 
through the 1970s, despite cessation of the production and use of these 
pesticides since the 1970s (Schiff et al., 2000). Although the input of 
pollutants into the SCB has declined since the 1970s, inputs by other 
sources (e.g., surface runoff from urban and agricultural watersheds) 
have remained steady or increased over time (Schiff et al., 2000).
    Mull et al. (2012) observed high concentrations of mercury, DDT, 
and PCBs in the liver and muscle tissues of YOY and juvenile white 
sharks caught in the SCB. The observed concentrations were 50 times 
higher than those observed in juvenile white sharks from South Africa 
(Schlenk et al., 2005) and in other species of sharks sampled from 
other parts of the world (Mull et al., 2012). Despite these high 
contaminant loads, deleterious physiological effects have not been 
documented in elasmobranchs (Mull et al., 2012). The high contaminant 
concentrations found in the tissues of young white sharks from the SCB 
suggest the potential for physiological effects, but such effects are 
unclear. The elevated selenium levels in the muscle tissues of the 
young SCB white sharks suggest a physiological response to counteract 
the elevated muscle mercury concentrations (Mull et al., 2012). In 
other species, uptake of selenium has been observed to counteract the 
toxicity of increased muscle mercury concentrations (Wiener et al., 
2003). In addition, hepatic lesions and other visible physical effects 
of high contaminant loads have not been observed in young NEP white 
sharks (Lyons, personal communication cited in Dewar et al., 2013).
    Overall, high contaminant concentrations have been observed in the 
tissues of young NEP white sharks, but the physiological effects of 
these high levels are not known. The high contaminant concentrations 
could indicate bioaccumulation from feeding in the SCB (Mull et al., 
2012) and/or maternal transfer of contaminants (Adams and McMichael, 
1999; Maz-Courrau et al., 2012; personal communication with Lyons, 
cited in Dewar et al., 2013). There is no information indicating that 
the NEP white shark population is being adversely affected at the 
population level as a result of contaminant bioaccumulation, and the 
BRT concluded that the risks of contaminants to the population was low 
overall (Dewar et al., 2013).

Competition

    In the 2 months immediately following an observed killer whale 
predation event on a white shark at the Southeast Farallon Islands, 
sightings of white sharks in the area dropped significantly compared 
with the frequency of sightings in previous years (Pyle et al., 1999). 
Although changes in prey abundance or environmental factors may have 
caused this decline in sightings, it is possible that it may have been 
the result of competitive displacement or predator avoidance (Pyle et 
al., 1999). Competitive displacement of white sharks by killer whales 
is possible given the overlap in the two species' distribution and 
prey, but interactions between the two species are poorly understood 
(Compagno, 2001).

Analysis of Other Natural or Manmade Factors

    Overall, the best available information regarding natural or 
manmade factors affecting the NEP white shark population do not 
indicate that these factors are contributing significantly to the risk 
of extinction for this population

Additional Information Received

    Oceana, Center for Biological Diversity, and Shark Stewards sent an 
email to the Secretary on May 23, 2013, attaching four 2013 white shark 
publications to ensure that we were aware of them. The BRT reviewed the 
first three publications (Domeier and Nasby-Lucas (2013); Mull et al. 
(2013); and Weng and Honebrink (2013)) before finalizing its status 
review report, so they were already considered. We have reviewed the 
fourth publication (Semmens et al. (2013)), and while we find the 
estimate of metabolic needs for white sharks interesting, metabolic and 
feeding rate estimates are not relevant to the question of whether the 
NEP white shark DPS is at risk of extinction. We have determined that 
prey are at low risk of being depleted or unavailable to the NEP white 
shark DPS, given improving stocks of fishes and marine mammals, and 
there is no evidence that food availability is affecting the DPS, so 
specific energetic requirements are not particularly relevant to our 
determination.

Listing Determination

    Based on our comprehensive status review including the BRT's 
findings (Dewar et al., 2013), which we agree with, our analysis of the 
five factors under Section 4(a)(1) of the ESA, and our review of public 
comments on the 90-day finding, we reached the following conclusions: 
(1) The NEP white shark population meets the discreteness and 
significance criteria of the joint NMFS-FWS DPS policy, and therefore, 
is a DPS under the ESA; (2) there are no identifiable portions of the 
NEP white shark DPS that constitute a significant portion of its range, 
and therefore, we evaluated the status of the DPS as a whole; (3) the 
total abundance of the NEP white shark DPS is uncertain, but 
information and analysis presented by the BRT (Dewar et al., 2013) 
indicates the population abundance is larger than the minimum estimates 
based on photo-ID studies at the central California and Guadalupe 
Island aggregation sites (Chapple et al., 2011 and Sosa-Nishizaki et 
al., 2012) and most likely includes at least 200 adult females; (4) the 
available information informing abundance trends suggests the NEP white 
shark DPS is most likely increasing or stable; (5) the main current and 
foreseeable future threat to the NEP white shark DPS is fishery-related 
mortality from U.S. and Mexican gillnet fisheries located in coastal 
waters of southern California and Baja California; (6) fisheries risk 
assessment modeling conducted by the BRT indicates the NEP white shark 
DPS is at a low to very low risk of extinction from U.S. and Mexican 
gillnet fisheries-related impacts and is likely to remain so in the 
foreseeable future; (6) the NEP white shark DPS is at a low to very low 
overall risk of extinction and is likely to remain so in the 
foreseeable future based on a consideration of the DPS' current 
biological status (i.e., current abundance includes at least 200 adult 
females and population is likely increasing in abundance or stable) and 
known threats, including fishery-related mortality; (7) identified 
threats related to habitat destruction or modification, disease and 
predation, or other natural and manmade factors are not considered 
significant and are not contributing to increasing the extinction risk 
of the DPS; and (8) existing regulatory mechanisms throughout the range 
of the NEP white shark DPS are adequately addressing threats to the 
population, although improvements are needed in Mexico to monitor and 
reduce fishery impacts.
    Based on these findings, we conclude that the NEP white shark DPS 
is not currently in danger of extinction throughout all or a 
significant portion of its range nor is it likely to become so within 
the foreseeable future. Accordingly, the NEP white shark DPS does not 
meet the definition of a threatened or endangered species and our 
listing determination is that the NEP

[[Page 40127]]

white shark DPS does not warrant listing as threatened or endangered at 
this time.

References

    A complete list of all references cited herein is available upon 
request (see FOR FURTHER INFORMATION CONTACT).

Authority

    The authority for this action is the Endangered Species Act of 
1973, as amended (16 U.S.C. 1531 et seq.).

    Dated: June 28, 2013.
Alan D. Risenhoover,
Director, Office of Sustainable Fisheries, performing the functions and 
duties of the Deputy Assistant Administrator for Regulatory Programs, 
National Marine Fisheries Service.
[FR Doc. 2013-16039 Filed 7-2-13; 8:45 am]
BILLING CODE 3510-22-P