Endangered and Threatened Wildlife and Plants; Notice of 12-Month Finding on Petitions To List the Northwest Atlantic Population of the Dusky Shark as Threatened or Endangered Under the Endangered Species Act (ESA), 74684-74695 [2014-29318]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 79, Number 241 (Tuesday, December 16, 2014)]
[Notices]
[Pages 74684-74695]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-29318]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[Docket No. 130214141-4999-02]
RIN 0648-XC515


Endangered and Threatened Wildlife and Plants; Notice of 12-Month 
Finding on Petitions To List the Northwest Atlantic Population of the 
Dusky Shark as Threatened or Endangered Under the Endangered Species 
Act (ESA)

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

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

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SUMMARY: We, NMFS, announce a 12-month finding on two petitions to list 
the Northwest Atlantic and Gulf of Mexico population of dusky shark 
(Carcharhinus obscurus) as a threatened or endangered distinct 
population segment (DPS) under the Endangered Species Act (ESA). We 
completed a comprehensive status review of the dusky shark in response 
to these petitions. Based on the best scientific and commercial 
information available, including the status review report (McCandless 
et al., 2014), we have determined that the Northwest Atlantic and Gulf 
of Mexico (henceforth abbreviated as NWA) population constitutes a DPS 
but does not warrant listing at this time. We conclude that the NWA DPS 
is not currently in danger of extinction throughout all or a 
significant portion of its range and is not likely to become so within 
the foreseeable future.

DATES: This finding was made on December 17, 2014.

ADDRESSES: The status review document for the dusky shark is available 
electronically at: https://www.nmfs.noaa.gov/pr/species/fish/duskyshark.htm. You may also receive a copy by submitting a request to 
the Office of Protected Resources, NMFS, 1315 East-West Highway, Silver 
Spring, MD 20910, Attention: Dusky Shark 12-month Finding.

FOR FURTHER INFORMATION CONTACT: Maggie Miller, NMFS, Office of 
Protected Resources, (301) 427-8403.

SUPPLEMENTARY INFORMATION:

Background

    On November 14, 2012, we received a petition from WildEarth 
Guardians (WEG) to list the dusky shark (Carcharhinus obscurus) as 
threatened or endangered under the ESA throughout its entire range, or, 
as an alternative, to list the Northwest Atlantic/Gulf of Mexico DPS as 
threatened or endangered. The petitioners also requested that critical 
habitat be designated for the dusky shark under the ESA. On February 1, 
2013, we received a second petition from Natural Resources Defense 
Council (NRDC) to list the Northwest Atlantic DPS of dusky shark as 
threatened, or, as an alternative, to list the dusky shark range-wide 
as threatened, and a request that critical habitat be designated. On 
May 17, 2013, we published a positive 90-day finding (78 FR 29100) 
announcing that the petitions presented substantial scientific or 
commercial information indicating the petitioned action of listing may 
be warranted for the NWA population of dusky shark, but not for the 
species range-wide, and explained the basis for that finding. We also 
announced the initiation of a status review of the NWA population of 
dusky shark, as required by section 4(b)(3)(a) of the ESA, and 
requested information to inform the agency's decision on whether the 
species warranted listing as endangered or threatened under the ESA.

Listing Species Under the Endangered Species Act

    We are responsible for determining whether species are threatened 
or endangered under the ESA (16 U.S.C. 1531 et seq.). To make this 
determination, we consider first whether a group of organisms 
constitutes a ``species'' under section 3 of the ESA, and then whether 
the status of the species qualifies it for listing as either threatened 
or endangered. Section 3 of the ESA defines a ``species'' to include 
``any subspecies of fish or wildlife or plants, and any distinct 
population segment of any species of vertebrate fish or wildlife which 
interbreeds when mature.'' On February 7, 1996, NMFS and the U.S. Fish 
and Wildlife Service (USFWS; together, the Services) adopted a policy 
describing what constitutes a DPS of a taxonomic species (the DPS 
Policy; 61 FR 4722). The DPS policy identified two elements that must 
be considered when identifying a DPS: (1) The discreteness of the 
population segment in relation to the remainder of the species (or 
subspecies) to which it belongs; and (2) the significance of the 
population segment to the remainder of the species (or subspecies) to 
which it belongs.
    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.'' 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. 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). In addition, we interpret 
``foreseeable future'' as the horizon over which predictions about the 
conservation status of the species can be reasonably relied upon.
    Section 4(a)(1) of the ESA requires us to determine whether any 
species is endangered or threatened due to any one or a combination of 
the following five threat factors: The present or threatened 
destruction, modification, or curtailment of its habitat or range; 
overutilization for commercial, recreational, scientific, or 
educational purposes; disease or predation; the inadequacy of existing 
regulatory mechanisms; or other natural or manmade factors affecting 
its continued existence. We are also required to make listing 
determinations based solely on the best scientific and commercial data 
available, after conducting a review of the species' status and after 
taking into account efforts being made by any state or foreign nation 
to protect the species.
    If we determine that a petitioned species meets the ESA definition 
of a ``species'' and warrants listing as threatened or endangered, we 
publish a proposed rule in the Federal Register and seek public comment 
on the

[[Page 74685]]

proposed listing. To determine if a species warrants listing as 
threatened or endangered, first we determine if it is threatened or 
endangered throughout its entire range. If it is not, then we need to 
consider whether it may qualify as threatened or endangered in a 
significant portion of its range per the Significant Portion of its 
Range Policy (79 FR 37577; July 1, 2014). This policy clarifies the 
Services' interpretation of the phrase ``significant portion of its 
range'' (SPR) in the definitions of ``threatened species'' and 
``endangered species.'' Under the policy, if we find that a species is 
threatened or endangered only in an SPR, individuals of the entire ESA 
species are listed wherever found. Under the SPR policy, the word 
``range'' is defined as the range occupied by the species at the time 
the Services make a listing determination under section 4 of the ESA. A 
portion of a species' range is defined as ``significant'' if: ``the 
species is not currently endangered or threatened throughout all of its 
range, but the portion's contribution to the viability of the species 
is so important that, without the members in that portion, the species 
would be in danger of extinction, or likely to become so in the 
foreseeable future, throughout all of its range.'' Finally, if the 
species is threatened or endangered in an SPR, and the population in 
that significant portion is a valid DPS, we will list the DPS rather 
than the entire taxonomic species or subspecies.

Status Review

    We convened a team of agency scientists to conduct the status 
review for the NWA dusky shark and prepare a report. The status review 
team (SRT) was comprised of two research fishery biologists from NMFS' 
Northeast and Southeast Fisheries Science Centers, a research 
mathematical statistician from the Alaska Fisheries Science Center, a 
fishery management specialist from NMFS' Highly Migratory Species 
Management Division, and two fishery biologists from NMFS' Greater 
Atlantic Regional Fisheries Office and the Office of Protected 
Resources. The SRT had group expertise in dusky shark biology and 
ecology, population dynamics, highly migratory species management, and 
stock assessment science.
    The status review report of the NWA dusky shark (McCandless et al., 
2014) compiles the best available information on the status of the NWA 
dusky shark as required by the ESA, provides an evaluation of the 
discreteness and significance of the NWA population in terms of the DPS 
policy, and assesses the current and future extinction risk for the NWA 
dusky shark, focusing primarily on the impacts of threats to the status 
of the species related to the five statutory factors set forth above.
    In assessing extinction risk, the SRT considered the demographic 
viability factors developed by McElhany et al. (2000) and the risk 
matrix approach developed by Wainwright and Kope (1999) to organize and 
summarize extinction risk considerations. The status review report 
presents the SRT's professional judgment of the extinction risk facing 
the NWA dusky shark but makes no recommendation as to the listing 
status of the species. The status review report is available 
electronically at https://www.nmfs.noaa.gov/pr/species/fish/duskyshark.htm.
    The status review 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). It was 
peer reviewed by three independent specialists selected from the 
academic and scientific community, with expertise in shark biology, 
conservation and management, stock assessment science, and knowledge of 
dusky sharks. The peer reviewers were asked to evaluate the adequacy, 
appropriateness, and application of data used in the status review 
report as well to evaluate the methods to assess extinction risk and 
the conclusions of the report. All peer reviewer comments were 
addressed prior to dissemination of the final status review report and 
publication of this determination.
    We subsequently reviewed the status review report, its cited 
references, and peer review comments, and believe the status review 
report, upon which this listing determination is based, provides the 
best available scientific and commercial information on the NWA dusky 
shark. Much of the information discussed below on dusky shark biology, 
distribution, abundance, threats, and extinction risk is attributable 
to the status review report. However, in making the listing 
determination, we have independently applied the statutory provisions 
of the ESA, including evaluation of the factors set forth in section 
4(a)(1)(A)-(E); our regulations regarding listing determinations; our 
DPS policy; and our SPR Policy.

Life History, Ecology, and Abundance of the Petitioned Species

Species Description

    The dusky shark is classified as a requiem shark within the family 
Carcharhinidae. This family falls under the largest order of sharks, 
Carcharhiniformes, also known as ground sharks. Dusky sharks, like many 
requiem sharks, appear gray or bluish-gray in color dorsally and white 
ventrally. The sharks within the genus Carcharhinus also have an 
internal nictitating eyelid, lack a spiracle, have a second dorsal fin 
that is less than half the height of the first, have well-developed 
pre-caudal pits, and a heterocercal caudal fin (Castro, 2011).

Range and Distribution

    Dusky sharks are coastal-pelagic sharks inhabiting temperate and 
tropical waters worldwide ranging from the surf zone, across 
continental and insular shelves, and adjacent oceanic waters from the 
surface down to 400 meters (m) depth (Compagno, 1984). In the NWA, 
dusky sharks range from off Cape Cod, Massachusetts and Georges Bank 
south to Florida, and also occur within the Gulf of Mexico and 
Caribbean Sea (Kohler et al., 1998; Kohler and Turner, 2010). This 
species does not use waters with reduced salinities and rarely enters 
estuarine environments (Compagno, 1984; Musick et al., 1993). During 
the summer months, small juveniles use nearshore coastal waters as 
nursery habitat in the NWA from off New Jersey to South Carolina 
(Castro, 1993; McCandless et al., 2007; NMFS, unpublished data).

Movement and Habitat Use

    The dusky shark is a highly migratory species that begins moving 
north during the spring and returns south during the fall months, often 
traveling the full extent of its range during these seasonal migrations 
(Compagno, 1984; Musick and Colvocoresses, 1986; Kohler et al., 1998, 
Kohler and Turner, 2010). Mark/recapture data from the NMFS Cooperative 
Shark Tagging Program between 1963 and 2013 show a maximum straight-
line distance traveled of 2,052 nautical miles (nm; 3,800 kilometers 
(km)), with a mean distance traveled of 572 nm (1,059 km) for dusky 
sharks tagged in the NWA (number tagged = 8,776 sharks; recaptures = 
181 sharks; Kohler and Turner, 2010; NMFS, unpublished data). Movements 
between the U.S. Atlantic and Gulf of Mexico (GOM), as well as between 
the U.S. GOM and Mexican Gulf waters were common, but there were no 
recaptures in the southwest Atlantic, and only one recapture off 
Central America (Barra de Colorado, Costa Rica) in the Caribbean Sea 
(Kohler and Turner, 2010; NMFS, unpublished data). Satellite tagging 
data from an aggregation site in the north central GOM during the 
summer months revealed dusky shark movements in

[[Page 74686]]

excess of 200 km (108 nm, Hoffmayer et al., 2014). These sharks 
primarily used offshore GOM waters associated with the continental 
shelf edge, spending 87 percent of their time in waters between 20 and 
125 m depth and 23 [deg]C and 30 [deg]C (Hoffmayer et al., 2014). 
Carlson and Gulak (2012) also tracked three dusky sharks off the U.S. 
Atlantic coast with pop up satellite tags and found that these sharks 
spent the majority of their time in water depths between 0 and 40 
meters with dives down to depths of 400 m. These sharks spent nearly 60 
percent of their time in water temperatures between 20 [deg]C to 24 
[deg]C. The dusky sharks generally traveled about 10 km per day. Two of 
the sharks were tagged near Key Largo, FL with one shark tagged in 
January traveling north to the North Carolina/Virginia border by June 
and the other tagged in March heading south towards Cuba two weeks 
later (Carlson and Gulak, 2012).

Diet

    The dusky shark is an apex predator with a high trophic level and 
diverse diet including bony fishes, cephalopods, elasmobranchs, decapod 
crustaceans, mollusks, and occasionally marine mammals (Cort[eacute]s, 
1999). Juveniles primarily consume pelagic bony fishes and cephalopods 
with an increase in the consumption of elasmobranch prey as their body 
size increases (Gelsleichter et al., 1999; Simpfendorfer et al., 2001). 
Stable isotope analysis has also shown a shift to shelf edge foraging 
in large dusky sharks (Hussey et al., 2011).

Reproduction and Growth

    The dusky shark is a placental, viviparous species, giving birth to 
between 2 and 16 pups per litter (Compagno, 1984; Romine, 2009; Castro, 
2011) with an average litter size of 7.13 pups for NWA dusky sharks 
(Romine, 2009). Size-at-birth for dusky sharks ranges from 85 to 100 
centimeter (cm) fork length (FL, Castro, 1983; Compagno, 1984). 
Available data on reproduction suggests a 3-year reproductive cycle 
(Castro, 2009; Romine, 2009) with a gestation period of 18 months 
(Castro, 2009). Female and male size at maturity in the NWA is 235 and 
231 cm FL (17.6 and 17.4 years of age), respectively (Natanson et al., 
1995; Natanson et al., 2013). Maximum validated age estimates are 
between 38 and 42 years, confirming longevity to at least 42 years of 
age (Natanson et al., 2013). Logistic growth parameters derived from 
validated vertebral length-at-age data are L [infin] = 261.5 
cm FL, Lo = 85.5 cm FL, to = 4.89 years and g = 0.15 year-1 
for the sexes combined (Natanson et al., 2013).

Genetics

    Genetic data can be used to provide information on a species' range 
as well as stock structure. Global phylogeographic studies of the dusky 
shark using maternally inherited mitochondrial DNA and nuclear 
microsatellite DNA analyses detected significant differentiation 
between dusky sharks from the NWA and Indo-Pacific regions, with waters 
off South America serving as a possible historical connection between 
these populations (Benavides et al., 2011; Gray et al., 2012). Despite 
the history of severe population declines in the NWA, dusky sharks from 
all regions showed remarkably similar allelic richness and gene 
diversity (Gray et al., 2012).
    The low nucleotide diversity for the dusky shark and the existence 
of a morphologically and genetically similar species (Galapagos shark, 
Carcharhinus galapagensis) indicates the dusky shark is recently 
derived on an evolutionary timescale (Naylor, 1992; Musick et al., 
2004; Benevides et al., 2011). An ongoing genetic study using 
mitochondrial DNA sequencing found that specimens identified as 
Galapagos sharks from oceanic islands in the NWA are indistinguishable 
from specimens identified as dusky sharks collected off the U.S. east 
coast from New Jersey to Florida (Gavin Naylor, College of Charleston, 
personal communication, 2014). These findings could possibly be 
attributed to an ancient hybridization event where there was a 
directional transfer of mitochondrial DNA genes, which are maternally 
inherited, from one species to another. Alternatively, they could 
represent two forms of the same species, an offshore and an inshore 
form. However, at this time, the evolutionary genetic relationship 
between the NWA dusky shark and Galapagos shark remains unresolved. 
Work continues on this using a wider global sampling scheme and 
multiple nuclear markers, which reflects the genetics of both parents, 
to address the possibility that the observed pattern might be the 
consequence of an ancient hybridization event. Whether or not these two 
species have the ability to interbreed (e.g., if the timing and 
location of opposite sexes ever co-occur during mating season), or if 
they would produce viable offspring is unknown.

Abundance Trends

    In 2011, the NWA dusky shark was assessed through the Southeast 
Data, Assessment, and Review (SEDAR) process, which is a cooperative 
Fishery Management Council process initiated in 2002 to improve the 
quality and reliability of fishery stock assessments in the South 
Atlantic, GOM, and Caribbean. Results from this SEDAR stock assessment 
base model indicated that NWA dusky shark abundance had declined 74 
percent from virgin (unexploited) levels by 2004, but was gradually 
increasing throughout the remainder of the time series modeled through 
2009 (NMFS, 2011a). The only two fishery-independent surveys that were 
used in this model, the Northeast Fisheries Science Center Coastal 
Shark Bottom Longline Survey (NELL) and the Virginia Institute of 
Marine Science Shark Longline Survey (VIMS LL), were recently updated 
with data from 2010 to 2012 (for NELL) and to 2013 (for VIMS LL) using 
the same methodology (delta-lognormal generalized linear mixed 
modelling) as was conducted for the SEDAR stock assessment (NMFS, 
2011a; McCandless et al., 2014). With these updates, the surveys show 
that the NWA relative abundance trends (based on numbers) have 
continued to increase.
    In addition, analysis of the University of North Carolina Shark 
Longline Survey (UNC LL) data, another fishery-independent time series 
that is still being conducted, also shows an increasing trend in 
abundance in recent years (McCandless et al., 2014). Although NWA dusky 
sharks are only second to the blacknose shark (Carcharhinus acronotus) 
in terms of numbers caught in the UNC LL survey, dusky sharks are 
transient in the sampled area and could easily be missed by the two 
fixed sampling stations. Because of these limitations, the UNC LL time 
series was recommended for use only in the sensitivity model runs for 
the SEDAR stock assessment to examine uncertainty in data inputs and 
model configuration (NMFS, 2011a). Analysis of data from this time 
series through 2009, included in the sensitivity model runs, revealed a 
declining trend in abundance for dusky sharks from the mid-1970s to the 
mid-1990s, with abundance appearing to stabilize at low levels into the 
2000s (Schwartz et al. 2010; NMFS, 2011a). However, the addition of 
recent data from 2010 to 2012 in the analysis has since given the model 
more information to determine a trend in recent years, and has, in 
fact, revealed an increasing trend in dusky shark abundance that began 
around 2006 (McCandless et al., 2014). In other words, with the data 
updates to all three of the above fishery-independent surveys, it 
appears that the NWA dusky shark abundance has been on a positive 
trajectory for almost the past decade.

[[Page 74687]]

Species Finding

    Based on the best available scientific and commercial information 
described above, we determined that Carcharinus obscurus is a 
taxonomically-distinct species and, therefore, meets the definition of 
``species'' pursuant to section 3 of the ESA. As noted above, the ESA's 
definition of ``species'' also includes ``any subspecies of fish or 
wildlife or plants, and any distinct population segment of any species 
of vertebrate fish or wildlife which interbreeds when mature.'' Below, 
we evaluate whether the petitioned NWA population of Carcharinus 
obscurus qualifies as a DPS based on the elements of discreteness and 
significance as defined in our DPS policy, to determine whether it is 
eligible for listing under the ESA.

Distinct Population Segment Analysis

    According to the SRT, the NWA population can be considered a 
discrete segment because it is markedly separate from other populations 
of dusky sharks as a consequence of genetic and physical/behavioral 
factors. Dusky shark populations have been reported in temperate and 
tropical waters worldwide, including the western Atlantic in the north 
from Nova Scotia to Cuba and the Gulf of Mexico, and in the south from 
Nicaragua to southern Brazil. Dusky sharks are also found in the 
Mediterranean, Indian, and western Pacific waters including off 
Madagascar and Australia, and in the eastern Pacific from southern 
California to the Gulf of California. Genetic studies, using both 
mitochondrial and nuclear microsatellite DNA, showed significant 
genetic differentiation between the western North Atlantic, South 
African, and Australian dusky shark populations, with a low frequency 
of migration between these populations (Benavides et al., 2011; Gray et 
al., 2012). Specifically, Benavides et al. (2011) found 25 
mitochondrial control region haplotypes and rejected a null hypothesis 
of panmixia (analysis of molecular variance, [Phi]ST = 0.55, 
p <0.000001), detecting significant differentiation between dusky 
sharks from the U.S. Atlantic, South Africa, and Australia. Work by 
Gray et al. (2012) supports these findings by identifying a strong 
divergence among NWA, South African, and Australian samples using 
microsatellite markers ([Phi]ST = 0.01-0.15, p <0.05).
    Within the western Atlantic, there is qualitative evidence of 
population structure between the NWA dusky sharks and dusky sharks 
caught off Brazil. The most common haplotype from Brazil is 
intermediate to the NWA and Indo-Pacific haplotype clusters, indicating 
this region may have provided a historical connection between the NWA 
and Indo-Pacific regions (Benavides et al., 2011). However, there was 
no evidence of genetic differentiation between dusky sharks from waters 
off the U.S. east coast and the GOM based on analysis of mitochondrial 
control regions (Benavides et al., 2011), suggesting that these 
populations readily mix.
    These genetic findings of a discrete population occurring within 
northwest Atlantic waters are further supported by tagging data 
collected from the NMFS Cooperative Shark Tagging Program between 1963 
and 2013 (Kohler et al., 1998; Kohler and Turner, 2010). Mark/recapture 
data from this program indicate that NWA dusky sharks commonly move 
between the U.S. Atlantic and GOM, as well as between the U.S. GOM and 
Mexican Gulf waters, but do not venture south of the Caribbean Sea 
(Kohler and Turner, 2010; NMFS, unpublished data). Although populations 
of dusky sharks occur off Brazil and South America, to date, no 
recaptures of the 8,776 tagged NWA dusky sharks have been identified 
from these areas, and only one has been recaptured within the Caribbean 
Sea (Kohler and Turner, 2010; NMFS, unpublished data). Given this 
behavioral information, it is likely that the dusky sharks found off 
Brazil and South America are independent from the NWA population of 
dusky sharks. Overall, based on the genetic and tagging study findings 
discussed above, we consider the NWA population of dusky sharks to be a 
discrete population.
    In terms of significance, the SRT determined that loss of the NWA 
segment would translate to a significant gap in the current range of 
the species, specifically the entire northwest Atlantic. Although 
qualitative data in Benavides et al. (2011) show a potential historical 
connection between the NWA and Indo-Pacific populations through the 
southwest Atlantic waters, the study indicates that recovery of 
depleted NWA populations would likely rely on reproduction by surviving 
local females as opposed to replenishment from immigrant females from 
the southwest Atlantic or Indo-Pacific. In other words, loss of the NWA 
population would leave a significant gap in the range of the species, 
extending from the Gulf of Maine south to Florida, and including the 
GOM and Caribbean Sea. As such, we consider the discrete NWA population 
of dusky sharks to be significant to the taxon as a whole.
    In conclusion, we agree with the SRT that the best available 
information indicates that the NWA population segment of dusky shark 
qualifies as a DPS under our DPS policy.

Summary of Factors Affecting the NWA DPS of Dusky Sharks

    We thoroughly reviewed the available information regarding 
historical, current, and potential threats to the NWA DPS of dusky 
sharks (McCandless et al., 2014). In the following section, we 
summarize information regarding each of these threats according to the 
factors specified in section 4(a)(1) of the ESA and consider whether 
any one or a combination of the factors are contributing to the 
extinction risk of the NWA DPS of dusky sharks.

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

    Based on our review of the best available information regarding 
historical and current range and habitat of the NWA DPS (McCandless et 
al., 2014), we found no evidence to suggest that the species has 
experienced a curtailment of its habitat or range, and there is little 
information that would suggest habitat destruction or modification is 
presently contributing or will contribute significantly to the NWA DPS' 
risk of extinction.
    In the U.S. exclusive economic zone (EEZ), the Magnuson-Stevens 
Fishery Conservation and Management Act (MSA) requires us to identify 
and describe essential fish habitat (EFH) in fishery management plans 
(FMPs), minimize the adverse effects of fishing on EFH, and identify 
actions to encourage the conservation and enhancement of EFH. The MSA 
defines EFH as ``those waters and substrate necessary to fish for 
spawning, breeding, feeding or growth to maturity.'' (16 U.S.C. 1802 
(10)). Towards that end, we have funded two cooperative survey programs 
intended to help delineate shark nursery habitats in the Atlantic and 
GOM. The Cooperative Atlantic States Shark Pupping and Nursery Survey 
and the Cooperative Gulf of Mexico States Shark Pupping and Nursery 
Survey are designed to assess the geographical and seasonal extent of 
shark nursery habitat, determine which shark species use these areas, 
and gauge the relative importance of these coastal habitats for use in 
EFH determinations. We also used fishery observer data, tagging data 
and fishery-independent sampling data to determine EFH for dusky 
sharks, as described in Amendment 1 to the 2006 Consolidated Atlantic 
Highly Migratory

[[Page 74688]]

Species (HMS) FMP (the FMP which manages the conservation of the 
domestic fisheries for Atlantic swordfish, tunas, sharks, and billfish) 
(NMFS, 2006; NMFS, 2009). These data resulted in the designation of EFH 
areas for neonate, juvenile, and adult dusky sharks in coastal and 
offshore waters from Florida to Cape Cod, which could provide important 
nursery habitats and breeding areas for this species.
    Next, we analyzed fishing and non-fishing impacts on EFH in the 
2006 Consolidated HMS FMP and concluded that while bottom longline gear 
(BLL), in general, may have an effect on EFH, shark BLL gear as 
currently used in the Atlantic shark fishery was not having more than a 
minimal and temporary effect on EFH. This BLL gear (which normally 
consists of a mainline between 3 and 8 km long with 200-400 hooks 
attached and is set for 2 to 20 hours) is primarily used in sandy and/
or muddy habitats where it is expected to have minimal to low impacts. 
Likewise, other HMS gears are not considered to have an impact on EFH. 
HMS gears do not normally affect the physical characteristics that 
define dusky shark habitat such as salinity, temperature, dissolved 
oxygen, and depth. Similarly, other state and federally managed gears 
were also determined not to have an impact on HMS EFH, with the 
possible exception of some bottom-tending gears in shark nursery areas 
in coastal bays and estuaries. However, we anticipate that any impacts 
resulting from these gears would be minimal and only temporary in 
nature (NMFS, 2009).
    We also found no information to suggest that non-fishing related 
activities are affecting dusky shark habitat in a significant way. 
Estuarine environments, which are most easily prone to degradation by 
human activity other than fishing, are rarely used by dusky sharks. 
Additionally, the NWA DPS is highly mobile throughout its range (as 
evidenced by results from tagging studies: Kohler and Turner, 2010; 
Carlson and Gulak, 2012; Hoffmayer et al., 2014; NMFS, unpublished 
data), and we found no evidence to suggest its access to suitable 
habitat is or will be restricted in the future.

Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    The NWA DPS of dusky shark is currently a prohibited species in 
U.S. Atlantic HMS fisheries (NMFS, 1999), meaning that neither U.S. 
commercial nor recreational fishermen are allowed to legally land this 
species; however, this was not always the case. During the late 1930s, 
a shark fishery developed off the east coast of Florida, in the GOM, 
and in the Caribbean Sea (Wagner, 1966), areas where the NWA DPS is 
known to occur. The shark fishery grew in response to the demand for 
vitamin A obtained from shark livers, but by the 1950s, most of these 
shark fisheries were abandoned due to the development of synthetic 
vitamin A (Wagner, 1966). In the late 1970s, the U.S. Atlantic shark 
fishery developed rapidly once again, this time due to increased demand 
for shark meat, fins, and cartilage worldwide. At the time, sharks were 
perceived to be underutilized as a fishery resource. The high 
commercial value of shark fins led to the controversial practice of 
``finning,'' or removing the valuable fins from sharks and discarding 
the carcasses during this time. Growing demand for shark products 
encouraged expansion of the commercial fishery throughout the late 
1970s and the 1980s. Tuna and swordfish vessels began to retain a 
greater proportion of their shark incidental catch and some directed 
fishery effort expanded as well. As catches accelerated through the 
1980s, shark stocks started to show signs of decline.
    The NWA DPS of dusky shark was not immune to this exploitation and 
followed the same trend as many of the other shark stocks off the U.S. 
east coast. Historically, the fishing mortality of the NWA DPS was 
estimated to be low from 1960 through the early 1980s, with the size of 
the NWA DPS predicted as being close to virgin levels until the late 
1980s (NMFS, 2011a). Fishing mortality was then thought to have 
increased to unsustainably high levels in the 1990s, before declining 
following the prohibition of dusky shark landings in 2000 (NMFS, 
2011a).
    In 2006, we assessed the status of the NWA dusky shark stock under 
the MSA and found it to be ``overfished'' with ``overfishing'' 
occurring (Cort[eacute]s et al., 2006; NMFS, 2007). The 2006 stock 
assessment predicted that dusky sharks could rebuild within 100 to 400 
years (Cort[eacute]s et al., 2006). In 2011, the NWA dusky shark stock 
was re-assessed through the more comprehensive SEDAR process (NMFS, 
2011a). Based on the results from this SEDAR assessment, we declared 
that the NWA dusky shark stock was still overfished and continues to 
experience overfishing (76 FR 62331; October 7, 2011); however, there 
was considerable uncertainty in the SEDAR stock assessment model about 
whether overfishing has occurred during the last several years of the 
time series (NMFS, 2011a; McCandless et al., 2014).
    The fishery management terms of ``overfishing'' and ``overfished'' 
are defined under the MSA and are based on different criteria than 
threatened or endangered statuses under the ESA. As such, they do not 
automatically indicate that a species may warrant listing under the ESA 
because they do not necessarily have any relationship to a species' 
extinction risk. Overutilization under the ESA means that a species has 
been or is being harvested at levels that pose a risk of extinction. 
Therefore, the analysis of the results from this most recent SEDAR 
stock assessment (NMFS, 2011a), catch and bycatch trends, and new data 
that have become available since the terminal year of the SEDAR stock 
assessment, are evaluated below in terms of insight into threats to the 
DPS and its likelihood of extinction.
    Although the NWA DPS of dusky sharks is currently a prohibited 
species in U.S. waters, individuals are still incidentally caught in 
the U.S. commercial BLL and pelagic longline (PLL) fisheries and U.S. 
gillnet fisheries (although rarely), and they have also been reported 
as landed in NMFS recreational fishing survey data. The SRT identified 
this bycatch as potential overutilization of the NWA DPS because it is 
the primary source of anthropogenic mortality of the DPS in U.S. 
waters. In assessing the impact of this bycatch mortality on extinction 
risk, we examined the results from the SEDAR stock assessment because 
the model implicitly included bycatch mortality in the calculations of 
total fishing mortality of the species. Due to the uncertainty about 
the magnitude of total catches and discards, an alternative modeling 
methodology was used in the SEDAR stock assessment, the Age-structured 
Catch Free Model (ASCFM), which re-scales the model population dynamics 
as proportional to unexploited conditions. Fishing mortality rates were 
estimated by the ASCFM using a correlated random walk prior. Although 
estimates of commercial at-vessel and commercial and recreational post-
release mortality for dusky sharks were included in the ``Data Workshop 
Report'' section of the SEDAR stock assessment report, these estimates 
were not directly inputted in the actual model (NMFS, 2011a). Pup 
survival was also estimated and given an informative lognormal prior 
(median=0.81, CV=0.3, and was bounded between 0.50 and 0.99). Relative 
effort series for the three primary U.S. fishing fleets that 
incidentally catch the NWA DPS (BLL, PLL, and recreational fleets) were 
used to determine a single, annual weighted

[[Page 74689]]

selectivity vector for modeling fishing mortality. In other words, 
although the SEDAR stock assessment used an ASCFM modeling approach, it 
still factored in total mortality attributable to fishing for its 
projections, which implicitly includes both discard mortality as well 
as mortality of those sharks retained in the catch. For these reasons, 
the at-vessel and post-release mortality associated with current trends 
of catch and bycatch should not negatively impact future stock 
projections. As such, the ASCFM base model stock assessment allows us 
to examine whether overutilization is still considered a threat to the 
species by modeling the effect of historical and current fishing 
mortality rates, including bycatch mortality, on the abundance trends 
and spawning stock biomass of the population.
    As mentioned before, overutilization under the ESA means that a 
species has been or is being harvested at levels that pose a risk of 
extinction and is most often indicated by a declining abundance and a 
low likelihood of a reversal of this trend due to this threat, or a 
combination of threats, and demographic risks. However, based on the 
SEDAR stock assessment model outputs, this does not appear to be the 
case. Although recruitment and spawning stock biomass have declined 
rather substantially since the late 1980s, spawning stock biomass 
levels are projected to maintain near 15 percent of unexploited levels 
into the future, indicating that the level of bycatch and landings and 
associated mortality at the time of the model (i.e., 2008 levels) is 
sustainable. In other words, recent exploitation levels do not appear 
to pose a risk of extinction to the NWA DPS as its biomass is projected 
to remain stable through the future.
    In addition, based on the estimates and trends of dusky shark 
bycatch from the available U.S. commercial BLL, PLL, gillnet, 
commercial handgear, and recreational fisheries data, we do not foresee 
a significant reversal in this biomass trend in the future, at least 
not in the negative direction. In terms of bycatch on BLL gear, the 
primary commercial gear employed for targeting large coastal sharks in 
all regions, the U.S. National Bycatch Report (NMFS, 2011b; NMFS 2013a) 
provides a comparison of estimates of dusky shark bycatch over the 
years from the GOM Reef Fish BLL commercial fishery. This comparison 
allows for insight into the bycatch trend for this fishery. For the 
time period of 2005 to 2006, the report estimated that annual dusky 
shark bycatch was approximately 798 individuals in the GOM Reef Fish 
BLL fishery (NMFS, 2011b). In an update to the report, for the years 
covering 2006 to 2010, the dusky shark bycatch in this fishery remained 
rather stable, with an annual estimate of 804 individuals (NMFS, 
2013a).
    Dusky shark bycatch in the U.S. Atlantic and GOM shark BLL fishery 
was included in the U.S. National Bycatch Report in pounds only and for 
the years of 2005 and 2006, but with the caveat that the estimates 
given were being refined due to discrepancies in the calculation of 
total effort (NMFS, 2011b). There was no reported dusky shark bycatch 
in the report update for the Atlantic and GOM shark BLL fishery so we 
are unable to evaluate the trend using this information (NMFS, 2013a). 
However, examination of observer data from the U.S. Atlantic and GOM 
shark BLL fishery indicates that NWA dusky sharks made up a small 
percentage of the total large coastal shark catch from 2005 to 2009 and 
showed a relatively stable trend across years (Hale et al., 2010). Out 
of 879 observed sets over the 5 years, only 8.2 percent of these sets 
caught dusky sharks (n=192 individuals). In the NMFS Shark Research 
Fishery, which has had 100 percent observer coverage since its creation 
in 2008 (NMFS, 2007), very low numbers of dusky sharks have been caught 
as bycatch (average=161 individuals from 2009 to 2012; Hale et al., 
2010; NMFS, 2011c; NMFS, 2012a; NMFS, 2013b) compared to overall 
bycatch estimates (NMFS 2011b; NMFS 2013a). Although there appears to 
be a minor increasing trend in the annual dusky shark bycatch in this 
fishery (y=38.9x-78047.2, R\2\=0.45, McCandless et al., 2014), analysis 
of fishing effort indicates there has been little change in effort from 
2009 through 2012. In other words, the increase in the bycatch amounts 
may be more likely attributed to increases in the relative abundance of 
dusky sharks within the NMFS Shark Research Fishery area, suggesting 
potential recovery of the NWA DPS within this area.
    In terms of bycatch on U.S. PLL gear, analysis of reported dusky 
shark catches from U.S. PLL logbook and observer data from 1992-2009 
showed similar trends, marked by an initial decrease in catch per unit 
effort (CPUE) in the 1990s followed by a more stable trend through the 
2000s (Cort[eacute]s, 2010), indicating that bycatch in the U.S. PLL 
fishery has potentially stabilized in recent years. The annual number 
of hooks deployed in the U.S. Atlantic PLL fishery, which is a 
representation of the level of fishing effort, has ranged from 
5,662,000 to 7,679,000 from 2003 to 2012, with no distinct pattern of 
increasing or decreasing effort (NMFS 2013a).
    In the U.S. gillnet fishery, NWA dusky shark bycatch is negligible. 
Since the implementation of Amendment 2 to the Consolidated Atlantic 
HMS FMP (NMFS, 2007), the directed large coastal shark (LCS) gillnet 
fishery has been greatly reduced. The 33-head LCS trip limit has 
essentially ended the strike net fishery and limited the number of 
fishermen targeting LCS with drift gillnet gear. As a result, many 
gillnet fishermen who historically targeted sharks are now targeting 
teleost species such as Spanish mackerel, king mackerel, and bluefish. 
In 2012, 316 sets comprising various gillnet fisheries were observed. 
During the strike gillnet trips, no dusky sharks were observed on trips 
that targeted king mackerel and only one dusky shark was caught during 
an observed sink net trip targeting smoothhound (Mathers et al., 2013).
    U.S. commercial handgears, including handline, harpoon, rod and 
reel, buoy gear and bandit gear, are also used to fish for Atlantic HMS 
by fishermen on private vessels, charter vessels, and headboat vessels. 
However, the shark commercial handgear fishery presently contributes 
very little to the overall dusky shark landings. The estimated annual 
NWA dusky shark bycatch in the GOM Reef Handline (vertical line) 
fisheries was approximately 256 individuals from 2006 to 2010, based on 
updated data to the U.S. National Bycatch Report (NMFS, 2013a). This 
reflects an 87 percent decrease from the previous annual estimate of 
approximately 1,941 individuals in 2006 (NMFS, 2011b) and was mainly 
attributed to the establishment and implementation of an individual 
fishing quota system for the GOM commercial red snapper fishery before 
the start of the 2007 fishing season.
    In terms of U.S. recreational catch, most Atlantic HMS are targeted 
by domestic recreational fishermen using a variety of handgear 
including rod and reel gear. Given that the NWA DPS is currently a 
prohibited species, only catch and release is allowed in the U.S. 
recreational fishery; however, landings of dusky sharks are still 
reported in NMFS recreational fishing survey data and, thus, are 
considered to be due to misidentification of the species (as dusky 
sharks are commonly confused with other Carcharhinid sharks (e.g., 
sandbar and silky sharks, Carcharhinus falciformis)) or fishermen not 
understanding the regulations. Given these issues, estimates of U.S. 
recreational catches of the NWA DPS are considered highly uncertain.

[[Page 74690]]

    Analysis of three data sources that estimated U.S. recreational 
dusky shark catches (the Marine Recreational Fishery Statistics Survey 
(MRFSS), the NMFS Headboat Survey (HBOAT) operated by the SEFSC 
Beaufort Laboratory, and the Texas Parks and Wildlife Department 
Recreational Fishing Survey (TXPWD)) shows that, by weight, the 
recreational landings and recreationally caught sharks that were killed 
but not landed appear to be of similar magnitude to the commercial 
discards in recent years, but shows no clear trend (Cort[eacute]s and 
Baremore, 2010). When data from these three surveys are combined by 
number, the total estimated recreationally landed and killed sharks 
from 2000 to 2009 depicts an overall decreasing trend (y=-346.7+696865, 
R\2\=0.30; data from Cort[eacute]s and Baremore, 2010). Although these 
data are highly uncertain, the available information indicates that 
mortality from recreational bycatch is not likely increasing.
    Analysis of the NMFS Large Pelagics Survey data from 1986 to 2009, 
where dusky sharks are primarily caught and released, shows that 
recreational NWA dusky shark catches exhibited a pattern of declines 
from the 1980s into the 1990s and a recent pattern of slight increases 
since 2000. Analysis of effort (shark directed trips) from 2003 to 2009 
also suggests very little change in total effort in recent years 
(y=7.8214x-15139, R\2\=0.0525, data from Walter and Brown, 2010), 
indicating that the increasing trend in catch rates may be attributed 
to increases in the relative abundance of dusky sharks within the areas 
fished (McCandless et al., 2014).
    Available data on Mexican shark landings and fishing effort 
indicate that even though Mexican fisheries likely contribute to dusky 
shark mortality, these impacts appear to have stabilized or be 
decreasing in recent years and are unlikely to lead to a significant 
reversal in the projected biomass trend of the NWA DPS. The Mexican 
shark fishery is part of a diverse multi-species artisanal fishery 
(Oviedo, 2010; Soriano-Vel[aacute]squez, 2011). The fleet uses both 
gillnet and longline gear to harvest sharks (Oviedo, 2010). The PLL 
gear is a selective gear, with yellowfin tuna making up over 70 percent 
of the catches (Brown and Ram[iacute]rez-L[oacute]pez, 2012). In 2006, 
shark species made up only 1.4 percent of the catch by numbers, and no 
dusky sharks were caught that year (Oviedo, 2010). During spring and 
summer, fleet activity is concentrated in the central, southern, and 
western portions of the Mexican EEZ and expands into the northern and 
eastern portions of the Mexican EEZ in the fall and winter (Brown and 
Ram[iacute]rez-L[oacute]pez, 2012). However, an analysis of PLL effort 
from 2001 to 2006 indicates that there has been very little change in 
fishing effort (y=30x-58212, R\2\=0.003, data from Brown and 
Ram[iacute]rez-L[oacute]pez, 2012).
    Based on an intensive monitoring study of Mexican artisanal shark 
landings from November 1993 to December 1994, Castillo-G[eacute]niz et 
al. (1998) reported that the Campeche region in the southeastern Gulf 
had the highest landings and effort, where Bonfil (1997) reported that 
dusky shark catches are rare. In 2010, Oviedo reported that there were 
1,813 fishing vessels documented fishing in Mexican waters in the GOM. 
Areas with the highest shark landings are reported to occur in Veracruz 
and Tamaulipas (Oviedo, 2010), where Bonfil (1997) reported that dusky 
shark catches were common with the addition of the Yucatan region. 
There is no known nursery habitat for dusky sharks in GOM waters within 
Mexico's EEZ, with primarily large juveniles and adults >1.5 m total 
length caught in the artisanal fisheries (Bonfil 1994, Bonfil 1997).
    In general, however, there has been an overall decline in Mexican 
shark landings from GOM fisheries in recent years (Soriano-
Vel[aacute]squez, 2011). A qualitative frequency analysis of landings 
from the southeastern GOM fisheries showed moderate dusky shark catches 
in the 1980s followed by low catches in the 1990s and no recorded dusky 
catches in the 2000s (Perez, 2011). The decline in shark landings is 
thought to be a result of past fishing pressure as well as rising fuel 
costs and shifts to other targets, such as rays and octopi (Soriano-
Vel[aacute]squez, 2011; Excart[iacute]n, 2011). Socio-economic research 
on Mexican artisanal fisheries reports that the artisanal fisheries in 
general are ``stagnant'' as many of the fishermen are older and younger 
people are less attracted to fishing as a career (Excart[iacute]n, 
2011). This study also indicates that the decline in shark catches 
within this region may be partially attributed to fishermen changing 
their target species to more profitable species such as the octopus, 
which is currently one of the most important commercial species and has 
increased landings in recent years (Excart[iacute]n, 2011). Therefore, 
based on the above information, it appears that the level of harvest of 
the NWA dusky shark by Mexican fishermen is likely minimal and also on 
the decline, as indicated by the decreasing trends in fishing effort.
    Overall, the combination of (1) the stable levels of the NWA DPS 
biomass into the future projected by the SEDAR stock assessment, 
indicating that the level of exploitation in 2008 was sustainable; (2) 
the evidence of stable and even decreasing NWA dusky shark bycatch, 
harvest trends, and fishing effort in U.S. commercial fisheries and 
Mexican fisheries; and (3) the catch rates from the NMFS Large Pelagics 
Survey, the NMFS Shark Research Fishery, and updated analyses of U.S. 
fishery-independent surveys (see Abundance Trends section), which all 
suggest increasing abundance trends in recent years, indicate that 
overutilization of the species in the form of U.S. bycatch and Mexican 
landings appears to no longer be a threat contributing significantly to 
the risk of the DPS' extinction.
    In terms of illegal harvest of the DPS, we did not find evidence 
that this is significantly contributing to the overutilization of the 
DPS. Since the mid-1990s, the United States Coast Guard (USCG) has been 
aware of Mexican fishing vessels fishing for sharks and other species 
in the U.S. Exclusive Economic Zone (EEZ) off the coast of Texas. The 
vessels originate from Matamoros, Mexico, and fish in the area 
surrounding South Padre Island, Texas, anywhere from zero to 20 miles 
(32 km) offshore. These vessels, or lanchas, fish during the day with 
gillnet and longline gear in U.S. waters for shark and red snapper, 
which are believed to be more prevalent in the U.S. EEZ off Texas than 
in the Mexican EEZ near Matamoros (Brewster-Geisz et al., 2010). 
However, analysis of detected fishery-related lancha incursions from 
2000 to 2009 show a recent decreasing trend since 2004 (y=-22.6x+45470, 
R\2\=0.81, Brewster-Geisz et al., 2010). In fact, since 2005, there has 
been a 46 percent decrease in the number of detected incursions 
(Brewster-Geisz et al., 2010). In addition, the majority of the sharks 
found on these lanchas are not dusky but rather blacktip and hammerhead 
sharks (Brewster-Geisz and Eytcheson, 2005).
    These illegally caught sharks are usually finned and the fins sold; 
however, the best available information on the international shark fin 
trade does not indicate that this level of utilization is likely of the 
magnitude to affect the status of the NWA DPS. In fact, a study by 
Clarke et al. (2006) estimated that dusky shark fins made up only 1.4 
percent (1.2-1.7 percent) of the auctioned fins in Hong Kong, the 
world's largest fin trading center. It was the second least encountered 
species in the fin auction (the first being tiger shark fins, 
Galeocerdo cuvier, comprising 0.13 percent of the fins at market, 
Clarke et al., 2006). It is also

[[Page 74691]]

unclear what proportion of the total dusky shark fins belonged to the 
prohibited NWA DPS. In addition, the primer that was used in the study 
to genetically identify fins of dusky sharks was unable to distinguish 
between dusky shark fins and Galapagos shark (C. galapagensis) fins; 
therefore, it is likely the reported percentage of dusky sharks in the 
fin market is overestimated (Clarke et al., 2006).
    Therefore, although some illegal harvest for dusky shark fins in 
the NWA may occur, the available information indicates that the present 
level of such illegal activity, especially for the fin trade, is 
minimal and we find it is unlikely to contribute significantly to the 
risk of the DPS' extinction.

Disease or Predation

    Various parasitic copepods have been documented on dusky sharks, 
including Alebion carchariae, Paralebion elongates, Perrisoppus 
communis, Pandarus satyrus, Pandarus sinuatus, Pandarus smithii, 
Pandarus cranchii, Nessipus alatus, Nessipus gracilis, Nessipus 
orientalis, Nemesis pallida, Nemesis spinulosis, Eudactylina spinifera, 
Kroyeria gracilis, and Opimia exilis (Bere, 1936; Cressey, 1970). 
Though there are many different types of parasitic copepods associated 
with dusky sharks, there are also species of diskfishes (Echenidae) 
that rely on the dusky shark for the host-fish relationship they 
provide for feeding on those copepods. Cressey and Lachner (1970) found 
the Remora remora and the ``white suckerfish'' (R. albescens) feed on 
copepods attached to dusky sharks. The connection between the host fish 
and R. remora was noted to be a stable, long-term relationship and that 
the white suckerfish is rarely caught apart from the host fish, which 
may indicate that these fish maintain a relationship with and/or close 
proximity to the host-fish (Cressey and Lachner, 1970).
    Acanthocephala, cestodes and trematodes have also been documented 
on dusky sharks (Linton, 1901; Linton, 1908; Linton, 1921; Bullard et 
al., 2004). Bullard et al. (2004) found a dusky shark in the Indian 
Ocean with Dermophthirius carcharhini, documenting the first record of 
the D. carcharhini distribution extending outside of the Atlantic 
Ocean. A dusky shark captured in the New York Bight and held in the New 
York Aquarium for 5 months suffered a mortal infection with D. 
carcharhini that was thought to show host specificity as it did not 
infect the other sharks present in the same tank (Cheung and Ruggieri, 
1983). Sea lampreys have also been documented on dusky sharks, though 
the extent of this occurrence is not known as sea lampreys tend to be 
opportunistic, feeding on a wide variety of bony and cartilaginous fish 
(Jensen and Schwartz, 1994; Wilkie et al., 2004; Gallant et al., 2006).
    Although dusky sharks experience some degree of parasitic disease, 
this does not appear to be a significant factor affecting the abundance 
or persistence of dusky shark populations in the wild, with the only 
mortality event due to parasitic disease recorded from a fish in 
captivity (Bullard et al., 2004). Additionally, as noted above, there 
are diskfishes that serve in a mutually beneficial relationship with 
dusky sharks feeding on the parasites.
    Like many other large coastal shark species, dusky sharks tend to 
be opportunistic feeders and occupy high trophic levels in the marine 
communities where they occur. Primarily a coastal species, but also 
found in the outer continental shelf and sometimes in pelagic waters 
(Castro, 2011), dusky sharks have a wide trophic spectrum that includes 
mostly fishes, cephalopods (squid, octopuses), other elasmobranchs 
(rays, other sharks), and crustaceans (Cort[eacute]s, 1999). Although 
some of their prey species may have experienced population declines, no 
information exists to indicate that depressed populations of these prey 
species are negatively affecting dusky shark population abundance. In 
addition, not much is known of resource partitioning and competition 
for resources in elasmobranch fishes in general, although both are 
likely to occur in marine communities of which sharks are a part 
(Wetherbee et al., 2012; Heithaus and Vaudo, 2012). It is possible that 
juvenile dusky sharks, in particular, may have to compete for food 
resources with other co-occurring sharks and teleosts, but it is 
unlikely that this competition for food would be important enough to 
affect their abundance, especially considering the high trophic 
plasticity and opportunistic behavior of large predatory species like 
the dusky shark (Cort[eacute]s et al., 2008).
    It is also very unlikely that predation on dusky sharks is a factor 
influencing their abundance. Adult dusky sharks reach a size of almost 
4 m and are considered the largest of the carcharhinid sharks (Castro, 
2011), with no major predators known. Owing to their large size at 
birth of about 1 m, it is also unlikely that newborn and juvenile dusky 
sharks have major predators that would regulate population size.

The Inadequacy of Existing Regulatory Mechanisms

    The NWA dusky shark receives a significant degree of regulatory 
protection in U.S. waters. In 2000, the dusky shark was added to list 
of prohibited shark species in the U.S. Atlantic. Since that time, U.S. 
commercial fishermen have not been allowed to retain, possess, land, 
sell, or purchase NWA dusky sharks, and recreational retention has also 
been prohibited, essentially affording the NWA DPS the highest level of 
fisheries protection under the MSA. (A review of Federal regulations 
pertaining to the NWA DPS prior to 2000 can be found in McCandless et 
al. (2014).) Projected apical fishing mortality relative to maximum 
sustainable yield levels for the NWA DPS has declined dramatically 
since 2000, indicating that this prohibition on the U.S. commercial and 
recreational retention of dusky sharks has directly and significantly 
decreased fisheries-related mortality of the species.
    In terms of state regulations, state fishery management agencies 
have authority for managing fishing activity only in state waters (0-3 
miles (0-5 km) in most cases; 0-9 miles (0-14 km) off Texas and the 
Gulf coast of Florida). In the case of federally permitted shark 
fisherman, fishermen are required to follow Federal regulations in all 
waters, including state waters, unless the state has more restrictive 
regulations. The Atlantic States Marine Fisheries Commission approved 
the Interstate FMP for Atlantic Coastal sharks in August 2008 to create 
consistent regulations across the Atlantic states from Maine to Texas. 
All Atlantic states, along with Puerto Rico and the U.S. Virgin 
Islands, have adopted the same prohibited status for the NWA DPS as the 
Federal regulations and those in the Interstate FMP for Coastal Sharks; 
therefore, commercial and recreational retention of NWA dusky sharks is 
prohibited in all U.S. Atlantic state and Federal waters.
    In addition to the prohibition, the NWA DPS also directly and 
indirectly receives a significant degree of protection from 
overutilization and fisheries-related mortality through the 
implementation of a number of other Federal regulations. For example, 
in 2005, we created the Mid-Atlantic Shark Closure Area, which 
encompasses North Carolina habitat for many dusky sharks. The area was 
closed to protect both dusky sharks and juvenile sandbar sharks from 
January through July. Data collected in the Shark Research Fishery and 
by NMFS scientists conducting BLL surveys in the Mid-Atlantic Shark

[[Page 74692]]

Closure Area indicate elevated interactions with dusky sharks during 
the time/area closure compared to outside the closed areas (NMFS, 
2012b), suggesting that this Mid-Atlantic Shark Closure area is 
providing protection to NWA dusky sharks from incidental fishing 
mortality.
    In the U.S. directed shark BLL fishery, where dusky sharks are 
known to suffer quite high at-vessel mortality (with an 81 percent at-
vessel mortality rate estimate, Morgan and Burgess, 2007; Romine et al. 
2009), commercial fishing impacts on dusky sharks have been greatly 
reduced since 2008 due to existing regulatory mechanisms. This is 
mainly a result of the U.S. management measure prohibiting the 
commercial harvest of sandbar sharks outside of the NMFS Shark Research 
Fishery (NMFS, 2012b), as implemented by Amendment 2 to the 2006 
Consolidated HMS FMP (NMFS, 2007). This prohibition ultimately resulted 
in shark fishermen targeting other species of sharks (e.g., blacktip, 
lemon, and bull sharks) that tend to occur in areas closer to shore 
than sandbar and dusky sharks (NMFS, 2014). Anecdotal evidence suggests 
that in the Atlantic Ocean, vessels that targeted sandbar sharks were 
more likely to catch dusky sharks because of similar habitat 
preferences, including depth and water temperature (NMFS, 2012b). 
Therefore, with the implementation of this regulation and the resultant 
shift in species targeted by commercial BLL fishermen, fishery-related 
mortality from the U.S. directed commercial BLL shark fishery has been 
significantly reduced and is considered to have only negligible impacts 
on the extinction risk of the species. This reduction has also likely 
led to the observed increase in the abundance of the species as 
indicated by the increasing trend in annual dusky shark bycatch in the 
NMFS Shark Research Fishery from 2009 through 2012 with little change 
in fishing effort (McCandless et al., 2014).
    Based on the findings above, the SRT concluded that the majority of 
current anthropogenic mortality of the NWA dusky shark can be 
attributed to U.S. PLL bycatch mortality, Mexican landings, and 
possibly mortality in the U.S. recreational fisheries from landings 
misidentifications and/or misunderstanding of the existing regulations. 
However, the U.S. PLL is a heavily managed gear type and the fishery is 
strictly monitored. Based on analyses using Pelagic Longline Observer 
Program data, the at-vessel mortality rate for dusky sharks in the U.S. 
PLL fishery has been estimated to be approximately 34 percent using 
data from 1992-2012 (NMFS, unpublished data) and 27.9 percent using 
data from 1995 to 2012 (Gallagher et al., 2014), significantly lower 
than rates on BLL gear. In other words, there is a higher likelihood 
that incidentally caught individuals on PLL gear can be released alive 
and continue to contribute to the viability of the NWA DPS. Regardless, 
additional measures to reduce interactions (e.g., time/area closures) 
with dusky sharks in the U.S. PLL fishery were proposed in Draft 
Amendment 5 to the 2006 Consolidated HMS FMP, but were not implemented, 
with further analyses being conducted on these measures in another FMP 
Amendment (Amendment 5b; NMFS, 2014). Management measures to correct 
the problems of misidentification or misunderstanding of U.S. 
recreational regulations have also not been implemented at this time; 
however, we have increased outreach efforts and education on proper 
identification and safe release practices for recreational shark 
fishing, including the publication of shark identification guides for 
U.S. recreational fishermen. Thus, although existing management 
measures may not suffice to further decrease the level of dusky shark 
mortality in the U.S. PLL and recreational fisheries, the current level 
of anthropogenic mortality experienced by the NWA DPS under these 
measures has been identified as sustainable (see Overutilization 
section) with the potential to decrease even further with current 
outreach efforts . Therefore, we do not find existing regulatory 
measures to be inadequate to the degree that they pose a threat to the 
species or contribute significantly to its risk of extinction.
    Additionally, states such as Delaware, Hawaii, Washington, 
California, Oregon, Illinois, New York, Maryland, and Massachusetts 
have implemented or are working towards the implementation of shark fin 
bans. These bans have been developed by states individually, but 
generally prohibit the purchase or sale of shark fin in the state. 
These bans may not have much of a direct impact on NWA DPS because of 
its prohibited status, but may have a broader impact on the shark 
fishing industry in general, especially if they lead to decreases in 
shark fishing effort which could indirectly lower the likelihood of 
dusky shark bycatch.
    In terms of Mexican regulations, the General Law of Sustainable 
Fishery and Aquaculture (Ley General de Pesca y Acuacultura 
Sustentables) regulates the use of living marine resources. Fishery 
management plans and regulations are implemented through the National 
Fishing Charter (CNP: Carta Nacional de Pesca). With authority under 
the CNP, and the National Plan of Action for the Conservation and 
Management of Sharks, Rays and Similar Species in Mexico (NPOA-Sharks), 
the National Fisheries Institute (INAPESCA: Instituto Nacional de 
Pesca) and the management agency, Comisi[oacute]n Nacional de 
Acuacultura y Pesca (CONAPESCA), implemented NOM 029-PESC-2006 (NOM: 
Norma Oficial Mexicana) called ``Responsible Fishery of Sharks and 
Rays; specifications for use.'' NOM 029-PESC-2006 regulates harvesting, 
designates prohibited species, specifies fishing zones and seasons, 
authorizes gears, and requires permit holders to report data. It 
promotes full use of shark catch by prohibiting finning. The goals are 
to maintain sharks at sustainable levels and reduce incidental catch of 
sea turtles and marine mammals. Additionally, CONAPESCA recently 
implemented an annual shark fishing prohibition in Mexican 
jurisdictional waters which began on the date of publication of the 
Agreement (June 11, 2012) through June 30, 2012, and in subsequent 
years is in effect during the period of May 1 to June 30 of each year. 
The prohibition extends to August 31 of each year in the Campeche Bank 
region. This regulation should help protect the NWA DPS from harvest 
mortality and may also deter future illegal fishing by Mexican 
fishermen, at least during the prohibition period.
    Challenges with existing Mexican regulations include poor 
enforcement, lack of compliance, and inaccurate logbook reporting due 
to its complex format. In response, CONAPESCA and INAPESCA prepared a 
shark ID guide, and are working to create a friendlier format. Overall, 
vast improvements in monitoring and regulating Mexican fisheries have 
been made in recent years, but many challenges still exist that may 
jeopardize the ability of NWA dusky shark populations to increase 
beyond current sustained levels. However, based on the evidence of 
stable and even decreasing NWA dusky shark fishing effort in Mexican 
fisheries coupled with low to no levels of catch in recent years, at 
this time, we do not find these existing regulatory measures to be 
inadequate to the point where they are contributing or will contribute 
significantly to the NWA DPS' risk of extinction.

Other Natural or Manmade Factors

    Many sharks are considered to be biologically vulnerable to 
overexploitation due to their life history traits, with demographic 
analyses often the tool used to assess this vulnerability. Productivity 
expressed as the intrinsic

[[Page 74693]]

rate of population increase (r) is the key parameter estimated from 
these analyses, with low estimates of r indicating a species that will 
be slow to recover from depletion. Musick (1999) suggested the 
following ranges for evaluating the productivity of marine species 
based on r (yr-\1\) values: High = >0.50, medium = 0.16-
0.50, low = 0.05-0.15, and very low = <0.05. Given the late age at 
maturity, slow growth rate, long life span, and low fecundity of many 
elasmobranchs, sharks are often at the low to very low end of this 
scale. In 2010, Cort[eacute]s et al. conducted an ecological risk 
assessment (ERA) of sharks caught in Atlantic PLL fisheries. The 
International Commission for the Conservation of Atlantic Tunas (ICCAT) 
recently updated this ERA in 2012 by adding five previously unassessed 
sharks, including the dusky shark. In this ERA (ICCAT, 2012), 
productivity for the dusky shark was modeled using updated life history 
information on age and growth from Natanson et al. (2013) and a 3-year 
reproductive cycle (Castro, 2009; Romine, 2009). Out of the 20 Atlantic 
shark stocks assessed by ICCAT (2012), the dusky shark stock had the 
fifth lowest intrinsic rate of population increase (r = 0.043 per 
year). Generation time was estimated at 29.6 years (ICCAT, 2012), which 
is 10 years shorter than the estimate that was used in the recent SEDAR 
dusky shark stock assessment (NMFS, 2011a). Although the productivity 
estimated by ICCAT (2012) nearly doubles the r (yr-\1\) 
values estimated during previous studies (r = 0.020, Smith et al., 
1998; r = 0.028, Cort[eacute]s, 1998; r = 0.018, Romine et al., 2009), 
bringing the relative rating of productivity from very low to 
borderline between very low and low (Musick, 1999), it still depicts a 
species vulnerable to overexploitation and susceptible to demographic 
and density-independent risks in the face of significant depletion. 
However, based on the evidence of increasing abundance and sustainable 
levels of exploitation of the NWA DPS, and the assessment of its 
current demographic and density-independent risks (discussed below in 
the ``Assessment of Demographic Viability Factors''), we do not find 
this biological vulnerability as currently inhibiting recovery or a 
threat that will contribute significantly to the NWA DPS' risk of 
extinction.
    Another factor that was evaluated as a potential threat to the NWA 
DPS was climate change. The effects of climate change are a growing 
concern for fisheries management as the distributions of many marine 
organisms are shifting in response to their changing environment. 
Factors having the most potential to affect marine species are changes 
in water temperature, salinity, ocean acidification, ocean circulation, 
and sea level rise. Two recent studies have addressed the vulnerability 
of dusky sharks to climate change. Chin et al. (2010) conducted a 
vulnerability assessment of sharks and rays on Australia's Great 
Barrier Reef (GBR) and we are in the process of finalizing a 
vulnerability assessment of U.S. northeast fish stocks (Jon Hare, 
NEFSC, personal communication, 2014). These studies identified similar 
factors for use in their vulnerability assessments, ranked the level of 
exposure and sensitivity to these factors using current knowledge and 
expert opinion, and based the resulting relative vulnerability for each 
species on simple logic rules. Dusky shark exposure rankings were 
highly influenced by water temperature, but sensitivity to this factor 
was ranked low for both the NWA and Australia's GBR sharks. NWA dusky 
sharks were assessed a high vulnerability ranking with respect to 
climate change, but this was primarily influenced by its MSA-defined 
stock status and population growth rate. Although the population growth 
rate was taken into account in the GBR study, little is known about the 
population status of sharks in this area (Chin et al., 2010; McAuley et 
al., 2012). GBR dusky sharks were assessed a low vulnerability ranking 
with respect to climate change. If the factor of stock status is 
removed from the NWA climate vulnerability analysis (or status is 
significantly improved) the overall vulnerability of dusky sharks to 
climate change would be assessed as low (Jon Hare, NEFSC, personal 
communication, 2014).
    Dusky sharks are not reliant on estuarine habitats, which are the 
habitats thought to be the most vulnerable to climate change. In 
addition, dusky sharks appear to prefer warmer temperatures and are 
frequently found in temperate to tropical water temperatures between 23 
[deg]C and 30 [deg]C. Although at-vessel mortality rates of dusky 
sharks were found to positively correlate with bottom water 
temperatures on BLL gear (Morgan and Burgess, 2007; Gallagher et al., 
2014), the effects of climate change on increased fishery-related 
mortality of the NWA DPS are likely to be minimal as previously 
discussed regulatory mechanisms have significantly reduced the 
likelihood of dusky shark capture in the U.S. commercial shark BLL 
fishery. Dusky sharks are also highly migratory and opportunistic 
predators, which gives them the ability to shift their range or 
distribution to remain in an environment conducive to their 
physiological and ecological needs. Based on the above information and 
analysis, we do not find that the impacts of warming water temperature 
from climate change will significantly contribute to the species' risk 
of extinction.

Assessment of Demographic Viability Factors

    In addition to the identification of threats, we also considered 
the collective condition of individual populations at the species level 
according to demographic viability factors but did not find evidence to 
indicate that these factors are appreciably reducing the fitness of the 
species. The NWA DPS is highly migratory and is not spatially 
restricted during any life stage, which contributes to its dispersal 
and re-colonization ability. The NWA DPS also exhibits high genetic 
diversity, with no indication that it is experiencing reduced 
reproductive fitness, fecundity, or survival due to loss of phenotypic 
diversity. Although the life history characteristics of the NWA DPS 
(long lived, late sexual maturity, low fecundity) limit the 
productivity of the species, rendering it less resilient to high levels 
of exploitation, its maximum rate of population increase is not 
decreasing nor are there indications that this productivity level could 
lead to extinction. In terms of abundance, it is difficult to make 
absolute statements about the number of dusky sharks in the NWA DPS 
because of the lack of reliable retention and discard data; however, 
fishery-independent surveys suggest that there are still a large number 
of dusky sharks in the U.S. Atlantic and GOM. In addition, although its 
current abundance has been significantly reduced from unexploited 
levels, there are multiple lines of evidence that indicate this number 
could be increasing (see Abundance section and analyses of data from 
the NMFS Shark Research Fishery and NMFS Large Pelagics Survey in 
Overutilization section). Overall, the NWA DPS does not appear to be at 
a point where normal environmental changes, anthropogenic 
perturbations, current fisheries-related mortality, habitat 
destruction, or demographic stochasticity could lead to its extinction.

Extinction Risk

    After considering the extent to which demographic viability factors 
may be indicating a risk of extinction and our evaluation of the ESA 
section 4(a)

[[Page 74694]]

factors impacts on the status of the species as discussed above, we 
find that the NWA DPS is presently at a low risk of extinction. This 
finding is in agreement with the SRT conclusions (McCandless et al., 
2014). The 2011 SEDAR stock assessment for this DPS indicated the 
population was depleted to around 85 percent of pre-exploitation 
levels; however, this assessment also suggested that the prohibition on 
dusky shark retention has come close to ending overfishing, with the 
projected biomass under existing management measures stabilizing near 
current values. Fishing mortality has significantly decreased since the 
U.S. commercial and recreational retention prohibition in 2000, with 
the present mortality of dusky sharks mainly attributed to bycatch 
mortality in the U.S. PLL fisheries and harvest by Mexican fishermen. 
However, U.S. PLL bycatch and Mexican landings appear to have 
stabilized at low levels in recent years, with trends that do not 
indicate any increases in fishing effort that would lead to extinction 
of this population. Additionally, fishery-independent survey indices 
(i.e., NELL, VIMS LL, UNC LL) and bycatch from the NMFS Shark Research 
Fishery and the NMFS Large Pelagic survey indicate that abundance 
trends for the NWA DPS have continued on a positive trajectory since 
the terminal year of the SEDAR stock assessment. There will always be 
some level of extinction risk associated with this DPS, given its 
inherent vulnerability to overexploitation and potential to suffer 
mortality when bycaught. However, based on the best available data that 
show stable to decreasing fishing effort, U.S. bycatch levels, and 
Mexican harvest, stabilizing spawning stock biomass, and increasing 
abundance trends, we consider the species to be at a low risk of 
extinction.
    In assessing the extinction risk of the species through the 
foreseeable future, the SRT defined the foreseeable future as the 
timeframe over which the threats to the species could be reliably 
predicted to impact the biological status of the species. Anthropogenic 
mortality from U.S. bycatch and Mexican landings and the species' 
natural biological vulnerability to overexploitation were the main 
operative threats that were likely to contribute significantly to the 
extinction risk of the NWA DPS. Since the main sources of NWA dusky 
shark bycatch (U.S. BLL and PLL fisheries) and Mexican landings appear 
to have stable, if not decreasing, trends since the last assessment, 
and the only change to management measures in place since that time has 
been the Mexican seasonal closure implemented in 2012, the SRT relied 
on the 2011 SEDAR stock assessment projection using the fishing 
mortality estimated for the final year of the assessment (F = 0.055; 
NMFS, 2011a) as a precautionary approach to determine the foreseeable 
future. As discussed previously, this SEDAR stock assessment model 
takes into account the species' life history information and projects 
the effects of anthropogenic mortality on the biomass of the species. 
However, due to the exponential increase in uncertainty seen in the 
projections of spawning stock biomass beyond 2045 (i.e., 
Fcurrent projection; NMFS, 2011a), the SRT decided that 30 
years was the extent of time over which they could confidently predict 
the impact of the operative threats on the species status. Thus, 
foreseeable future was defined as 30 years.
    In terms of extinction risk, we find that the NWA DPS will be at a 
low risk of extinction through the foreseeable future. This is also in 
agreement with the SRT, who was fairly certain that the NWA dusky shark 
DPS will have a low to no risk of extinction in the foreseeable future 
and will likely show improvement from its current status. For all SEDAR 
projection scenarios using data from the most recent SEDAR stock 
assessment, spawning stock biomass is predicted to either stabilize 
through the foreseeable future (based on the 2008 estimated fishing 
mortality) or increase (based on alternate projections taking into 
account potential changes in fishing mortality that likely would 
require changes to current management measures) (NMFS, 2011a). The SRT 
did note that the greatest source of uncertainty in the SEDAR stock 
assessment data was the amount of human induced removals, with the 
projections of NWA dusky shark status most sensitive to the inclusion 
of different abundance indices and the weighting of these indices. For 
example, if total fishing mortality was underestimated or productivity 
was overestimated, there could be some cause for concern regarding the 
future status of the species (as exhibited by the lower 5-10 percent 
quantiles of biomass projections; NMFS, 2011a). However, recent and 
sustained positive trends in dusky shark abundance indices with updated 
data that was not considered in the projection suggests that the point 
estimates for exploitation levels (fishing mortality) may have been 
biased high and estimates of stock biomass may have been biased low 
given that an increase in biomass was not predicted for 2010-2012 by 
the SEDAR stock assessment model (NMFS, 2011a). Additionally, estimates 
of the species' productivity have increased, based on updated life 
history information since the last assessment was conducted, suggesting 
the potential biases mentioned above are not operative.

Final Determination

    Section 4(b)(1) of the ESA requires that we make listing 
determinations based solely on the best scientific and commercial data 
available after conducting a review of the status of the species and 
taking into account those efforts, if any, being made by any state or 
foreign nation, or political subdivisions thereof, to protect and 
conserve the species. We have independently reviewed the best available 
scientific and commercial information including the petition, public 
comments submitted on the 90-day finding (78 FR 29100; May 17, 2013), 
the status review report (McCandless et al., 2014), and other published 
and unpublished information, and have consulted with species experts 
and individuals familiar with the dusky shark.
    We conclude that the dusky sharks occurring in the NWA are discrete 
and significant from other members of their species and, therefore, we 
consider this population to be a DPS. Next, we considered each of the 
ESA section (4)(a)(1) factors to determine whether it presented an 
extinction risk to the NWA DPS on its own. We also considered the 
combination of those factors to determine whether they collectively 
contributed to the extinction of the species. Our determination set 
forth below is based on a synthesis and integration of the foregoing 
information, factors and considerations, and their effects on the 
status of the NWA DPS throughout its entire range.
    We conclude that the NWA DPS of dusky shark is not presently in 
danger of extinction, nor is it likely to become so in the foreseeable 
future throughout all of its range. We summarize the factors supporting 
this conclusion as follows: (1) The DPS is highly migratory, occurring 
throughout its range, with no barrier to dispersal; (2) its current 
range is indistinguishable from its historical range, and there is no 
evidence of habitat loss, destruction, or modification that is 
significantly contributing to the species' extinction risk; (3) there 
is no evidence that disease, predation, or competition is contributing 
to increasing the risk of extinction of the species; (4) while the 
species possesses life history characteristics that increase its 
susceptibility to depletion, current abundance levels are sufficient to

[[Page 74695]]

maintain population viability now and into the foreseeable future; (5) 
stock assessment projections and trends in catch data and updated 
fishery-independent time series indicate increasing abundance of the 
NWA DPS, with spawning stock biomass stabilizing through the 
foreseeable future; (6) while the main threat to the species is 
fishery-related mortality from bycatch in U.S. commercial and 
recreational fisheries and Mexican landings, U.S. bycatch and Mexican 
harvest under existing management measures has decreased and/or 
stabilized at low levels in recent years, with current levels deemed 
sustainable through the foreseeable future; (7) existing regulatory 
mechanisms throughout the DPS' range, including the U.S. retention 
prohibition as well as time and area closures in both U.S. and Mexican 
waters and strict management of the U.S. line fisheries, appear 
effective in addressing the most important threat to the species (i.e., 
exploitation through bycatch mortality and harvest); and (8) while the 
NWA DPS has declined from historical numbers, there is no evidence that 
the species is currently suffering from depensatory processes (such as 
reduced likelihood of finding a mate or mate choice or diminished 
fertilization and recruitment success) or is at risk of extinction due 
to environmental variation or anthropogenic perturbations. Accordingly, 
the NWA DPS of dusky shark does not meet the definition of a threatened 
or endangered species, and our listing determination is that the NWA 
DPS of dusky shark does not warrant listing as threatened or endangered 
at this time.

Significant Portion of Its Range

    Because we find that the species does not warrant listing as 
threatened or endangered throughout its range, we must evaluate whether 
there is substantial information indicating that a portion of the 
species' range is both significant and either threatened or endangered 
per the Significant Portion of its Range Policy (79 FR 37577; July 1, 
2014). However, after a review of the best available information, we 
could not identify a portion of the NWA DPS range where its 
contribution to the viability of the species is so important that, 
without the members in that portion, the NWA DPS would be at risk of 
extinction, or likely to become so in the foreseeable future, 
throughout all of its range. The NWA DPS is highly mobile throughout 
its range. Loss of any portion of its range would not likely isolate 
the species to the point where the remaining portions would be at risk 
of extinction from demographic processes. Similarly, we did not find 
that loss of any portion would severely fragment and isolate the NWA 
DPS to the point where individuals would be precluded from moving to 
suitable habitats or have an increased vulnerability to threats. In 
fact, we found no information that would suggest that the remaining 
populations could not repopulate the lost portion. There are very few 
restrictions governing their movements, with individuals of the DPS 
commonly moving between the U.S. Atlantic, U.S. GOM and Mexican Gulf 
waters based on mark/recapture studies (Kohler and Tuner 2010; Carlson 
and Gulak, 2012; NMFS, unpublished data). Individuals of the species 
also tend to travel the extent of their range during their seasonal 
migrations (Compango, 1984; Musick and Colvocoresses, 1986; Kohler et 
al., 1998; Kohler and Turner, 2010). Areas exhibiting source-sink 
dynamics, which could affect the survival of the species, were not 
evident in any part of the NWA DPS range.
    There is no information that the loss of genetic diversity from one 
portion (such as the Atlantic Ocean) would result in the remaining 
population lacking enough genetic diversity to allow for adaptations to 
changing environmental conditions. Dusky sharks from all regions show 
remarkable similar allelic richness and gene diversity, and within the 
NWA there was no evidence of genetic differentiation between dusky 
sharks from waters off the U.S. east coast and the GOM (Benavides et 
al., 2011; Gray et al., 2012).
    There is also no evidence of a portion that encompasses aspects 
that are important to specific life history events but another portion 
that does not, where loss of the former portion would severely impact 
the growth, reproduction, or survival of the entire species. EFH areas, 
which could provide important nursery, breeding, and feeding grounds, 
have been identified along the length of the U.S. east coast, with 
smaller localized areas in the central GOM, southern Texas, the Florida 
Panhandle, mid-west coast of Florida, and Florida Keys (NMFS, 2009). 
Given that the environmental characteristics that constitute this EFH, 
such as warm waters with reduced salinities, nearshore coastal waters, 
and waters associated with the continental shelf edge, can be found 
throughout the species' range, we do not consider them to be limiting 
factors for the species' survival. In other words, the viability of the 
species does not appear to depend on the productivity of the population 
or the environmental characteristics in any one portion.
    Additionally, in our evaluation of the potential threats to the 
species, including the likelihood of fishery-related mortality, we did 
not find information to show that these threats are significantly 
concentrated or substantially greater in any specific portion of the 
species' range. The dusky shark is susceptible to being caught as 
bycatch in U.S. commercial and recreational fisheries throughout the 
entire extent of its range and is landed in Gulf waters by Mexican 
fishermen; however, we found no information to suggest that increased 
effort in a certain area is leading to a higher risk of extinction for 
that portion. Again, there are no barriers to the shark's movement and 
existing management measures appear adequate in protecting the NWA DPS 
from extinction throughout all portions of its range.
    In conclusion, we find that there is no portion of the NWA DPS 
range that can be considered significant under the SPR Policy. 
Therefore, we find that the NWA DPS is not presently in danger of 
extinction throughout all or a significant portion of its range, nor is 
it likely to become so in the foreseeable future, and, as such, does 
not warrant listing 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: December 9, 2014.
Samuel D. Rauch III,
Deputy Assistant Administrator for Regulatory Programs, National Marine 
Fisheries Service.
[FR Doc. 2014-29318 Filed 12-15-14; 8:45 am]
BILLING CODE 3510-22-P