Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition to List the San Francisco Bay-Delta Population of the Longfin Smelt (Spirinchus thaleichthys, 16169-16175 [E9-8087]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 74, Number 67 (Thursday, April 9, 2009)]
[Proposed Rules]
[Pages 16169-16175]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-8087]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R8-ES-2008-0045; MO 922105 0083-B2]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition to List the San Francisco Bay-Delta Population of the 
Longfin Smelt (Spirinchus thaleichthys) as Endangered

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to list the San Francisco Bay-Delta 
population of the longfin smelt (Spirinchus thaleichthys) as endangered 
with critical habitat under the Endangered Species Act of 1973, as 
amended (Act). After a thorough review of all available scientific and 
commercial information, we find that the San Francisco Bay-Delta 
population of the longfin smelt does not meet our definition of a 
distinct population segment (DPS), as identified in our DPS policy (61 
FR 4721, February 7, 1996). As a result, listing the species as a DPS 
is not warranted. However, we are initiating a status assessment of the 
longfin smelt, and we solicit information on the status of the species 
range wide.

DATES: The finding announced in the document was made on April 9, 2009.

ADDRESSES: This finding is available on the Internet at https://www.regulations.gov and https://

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www.fws.gov/sacramento. Supporting documentation we used in preparing 
this finding are available for public inspection, by appointment, 
during normal business hours at the U.S. Fish and Wildlife Service, 
Sacramento Fish and Wildlife Office, 2800 Cottage Way, Room W-2605, 
Sacramento, CA 95825; telephone 916-414-6600; or facsimile 916-414-
6712. Please submit any new information, materials, comments, or 
questions concerning this finding to the above street address or fax.

FOR FURTHER INFORMATION CONTACT: For information on this finding, 
contact Susan Moore, Field Supervisor, or Arnold Roessler, Listing 
Program Coordinator, of the Sacramento Fish and Wildlife Office (see 
ADDRESSES). If you use a telecommunications device for the deaf (TDD), 
call the Federal Information Relay Service (FIRS) at 1-800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

    Section 4(b)(3)(B) of the Act (16 U.S.C. 1531 et seq.) requires 
that, for any petition containing substantial scientific and commercial 
information indicating that listing may be warranted, we make a finding 
within 12 months of the date of our receipt of the petition on whether 
the petitioned action is: (a) not warranted, (b) warranted, or (c) 
warranted, but the immediate proposal of a regulation implementing the 
petitioned action is precluded by other pending proposals to determine 
whether any species is threatened or endangered, and expeditious 
progress is being made to add or remove qualified species from the 
Lists of Endangered and Threatened Wildlife and Plants. Such 12-month 
findings are to be published promptly in the Federal Register. This 
finding is based on our determination, based on the limited evidence 
available, that the San Francisco Bay-Delta population of longfin smelt 
is not a valid distinct population segment (DPS) under our Distinct 
Population Segment Policy (61 FR 4721, February 7, 1996), and, 
therefore, cannot be considered a listable entity under section 3(16) 
of the Act.

Previous Federal Actions

    On August 8, 2007, we received a petition from the Bay Institute, 
the Center for Biological Diversity, and the Natural Resources Defense 
Council to list the San Francisco Bay-Delta population of the longfin 
smelt as a distinct population segment (DPS) and designate critical 
habitat for the species concurrent with the listing. The petition was 
clearly identified as a petition for a listing rule and contained the 
names, signatures, and addresses of the requesting parties. On May 6, 
2008, we published a 90-day finding (73 FR 24911) in which we concluded 
that the petition provided substantial information indicating that 
listing San Francisco Bay-Delta Population of the longfin smelt as a 
DPS may be warranted, and we initiated a status review. However, in 
that notice, we did not make a final determination that the San 
Francisco Bay-Delta Population of the longfin smelt was a DPS; we only 
stated that the petition presented substantial information indicating 
that listing as a DPS may be warranted and that we would finalize our 
determination in our status review. This notice constitutes the 12-
month finding on the August 8, 2007, petition to list the San Francisco 
Bay-Delta population of the longfin smelt as a DPS and designate 
critical habitat for the species concurrent with the listing.

Species Description

    The following species description is taken from U.S. Fish and 
Wildlife Service 1995, p. 47, except where cited otherwise. Longfin 
smelt is a pelagic (lives in open water), estuarine fish that typically 
measures 3.5 to 4.3 inches (in) (90-110 millimeters (mm)) standard 
length, although third-year females may grow up to 5.9 in (150 mm) 
(Moyle 2002, p. 236). The sides and lining of the gut cavity appear 
translucent silver, the back has an olive to iridescent pinkish hue, 
and mature males are usually darker in color than females. Longfin 
smelt can be distinguished from other smelts in California by their 
long pectoral fins, incomplete lateral line, weak or absent striations 
on their opercular (covering the gills) bones, low numbers of scales in 
the lateral series (54 to 65), and long maxillary bones (in adults, 
these bones extend just short of the posterior margin of the eye).

Taxonomy

    The longfin smelt belongs to the true smelt family Osmeridae, and 
is one of three species in its genus; the night smelt (Spirinchus 
starksi) co-occurs in California and the shishamo (S. lanceolatus) 
occurs in northern Japan (McAllister 1963, pp. 10 and 15). Because of 
its distinctive characteristics, the San Francisco Bay-Delta population 
of longfin smelt was once described as a species separate from more 
northern populations (Moyle 2002, p. 235). McAllister (1963, p. 12) 
merged the two species, S. thaleichthys and S. dilatus, because the 
difference in morphological characters represented a north-south cline 
rather than a discrete set; a subsequent study using electrophoresis of 
allozymes (proteins used as genetic markers because DNA contains 
information that is used by cells to build proteins) showed that 
populations from Lake Washington near Seattle, Washington, and the 
Sacramento-San Joaquin Delta in California are similar genetically 
(Stanley et al. 1995, p. 390). The study did, however, find that the 
Sacramento-San Joaquin Delta population of longfin smelt differs in 
allele (alternative form of a gene) frequencies from the population in 
Lake Washington (Stanley et al. 1995, p. 390). Delta smelt and longfin 
smelt hybrids have been observed in the San Francisco Bay-Delta 
estuary, although these offspring are not thought to be fertile because 
delta smelt and longfin smelt are not closely related taxonomically or 
genetically (California Department of Fish and Game (CDFG) 2001, p. 
473).

Biology

    The longfin smelt is a euryhaline (tolerant of variable salinities) 
pelagic fish that inhabits various depths of the water column depending 
on the individual's life stage. Longfin smelt have been found 
throughout the year in fresh and brackish waters with salinities 
ranging from 14 to 28 parts per thousand (ppt) (CDFG 2001, p. 477). 
Adults can typically be found in the middle or lower part of the water 
column (Moyle 2002, p. 236), while larvae maintain position in the 
upper part of the water column, where they are usually found. Longfin 
smelt reportedly cannot tolerate water temperatures greater than 68 
degrees Fahrenheit ([deg]F) (20 degrees Celsius ([deg]C)) (Moyle 2002, 
p. 236), and will move farther downstream (west) during the summer 
months when water temperatures in the Delta are higher. Adult longfin 
smelt occupy water at temperatures from 61 to 68 [deg]F (16 to 20 
[deg]C), with spawning probably occurring in water with temperatures 
between 44.5 to 58 [deg]F (7.0 to 14.5 [deg]C) (Wang 1986, pp. 6-9).
    Longfin smelt prey primarily on opossum shrimp (Neomysis mercedis) 
and other small crustaceans (Acanthomysis sp.), although copepods such 
as the calanoid copepod (Pseudodiatomus forbesi) and cyclopoid copepod 
(Acanthocyclops vernalis) (Hobbs et al. 2006, p. 907) and other 
crustaceans are also preyed upon, especially by smaller fish (Moyle 
2002, p. 236). Longfin smelt are preyed upon by fishes, birds, and 
mammals (Barnhart et al. 1992, p. 44) and are a major prey item of 
harbor seals (Phoca vitulina) in the Columbia River (Service 1995, p. 
51). Predation of longfin smelt in the San Francisco Bay Estuary is 
known to occur by both striped bass (Morone

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saxatilis) and inland silversides (Menidia beryllina), but the effects 
of predation on the population are not well understood (Moyle 2002, p. 
238). In the ocean, longfin smelt feed primarily on small crustaceans, 
but may also feed on jellyfish and larval fish (Barnhart et al. 1992, 
p. 44).

Reproduction

    Longfin smelt may spawn as early as November and as late as June, 
although typically spawning occurs from February to April (Moyle 2002, 
p. 236). However, longfin smelt at various life stages are detected in 
the San Francisco Bay estuary trawl surveys in numerous months of the 
year (Rosenfield and Baxter 2007, p. 1578), suggesting that the 
spawning period may not be restricted to November to June or that 
growth and development between individuals varies. Spawning occurs in 
areas of relatively low salinity, which are considered essential 
nursery habitat for estuarine organisms (Jassby et al. 1995, p. 284). 
Spawning usually occurs over rocky or gravelly substrates and aquatic 
plants (Moyle 2002, p. 236). Female longfin smelt produce between 5,000 
to 24,000 eggs which stick to the substrate, and hatch within 40 days 
depending on the water temperature (CDFG 2001, p. 477). Newly hatched 
embryos are transported in the upper portion of the water column 
downstream (west) into more brackish parts of the San Francisco Bay-
Delta system (Moyle 2002, p. 236). Longfin smelt usually live for 2 
years, although some individuals may spawn as 1- or 3-year-old fish 
(Moyle 2002, p. 236), and die soon after spawning.

Range and Extant Distribution

    The historical and current range of the longfin smelt is from 
Alaska southward to the San Francisco Bay-Delta in California, which 
includes the Delta, Suisun Marsh, San Pablo Bay, and the San Francisco 
Bay to the Golden Gate. One fish was found in the Monterey Bay (south 
of the San Francisco Bay-Delta) in California (Eschmeyer 1983, p. 82; 
Wang 1986, pp. 6-10). In Alaska, longfin smelt are known from 
Hinchinbrook Island, Prince William Sound, Dixon Entrance, Yakutat Bay, 
and Cook Inlet (Alaska Natural Heritage Program (ANHP) 2006, p. 3). In 
Washington, the range includes Willapa Bay, Skagit Bay, Columbia River, 
Grays Harbor, and Puget Sound; in Oregon, the range includes Coos Bay 
and Yaquina Bay (ANHP 2006, p. 3). Relative to longfin smelt in the San 
Francisco Bay-Delta, the nearest confirmed breeding population of 
longfin smelt occurs in the Columbia River, approximately 640 miles 
(mi) (1,029 kilometers (km)) north of the San Francisco Bay-Delta 
(Randall Baxter, CDFG, pers. comm. 2008). In California, longfin smelt 
are known from (north to south) the Klamath River, Humboldt Bay and its 
tributaries, the Eel River, the Van Duzen River, the Russian River, and 
the San Francisco Bay-Delta (Moyle 2002, p. 235). The species was 
previously described as ``weakly anadromous'' (Fry 1973, p. 88); 
however, new research has found that at least part of the San Francisco 
Bay-Delta population is anadromous (living mostly in the ocean and 
spawning in fresh water) (Rosenfield and Baxter 2007, p. 1590). Non-
anadromous land-locked populations occur in Lakes Harrison and Pit in 
British Columbia, and Lakes Washington and Union in Washington (Page 
and Burr 1991, p. 57).
    Longfin smelt are dispersed broadly in the San Francisco Bay-Delta 
estuary by high outflows and currents, which could transport larvae or 
small juveniles long distances before they mature and become demersal 
(living near the bottom of the water column) (Baxter 2008, p. 1). 
Unverified reports exist of longfin smelt being captured 3 to 4 mi (5 
to 6 km) offshore in northern California (Service 1994, p. 3), but the 
ecology and behavior of longfin smelt in the open ocean remains largely 
unstudied. We are unaware of any studies assessing the swimming 
abilities of longfin smelt, but they may be comparable to juvenile 
salmon with the capability of swimming back into estuaries from the 
ocean (Moyle 2008, p. 1). We believe it is likely that individuals from 
the San Francisco Bay-Delta estuary population could be transported via 
ocean currents, north to the Russian River, Eel River/Humboldt Bay, and 
Klamath River estuaries, particularly during high outflow years, which 
are associated with northward ocean currents in the winter. It is also 
likely that individuals from northern estuaries may be transported to 
the San Francisco Bay-Delta estuary via southward (summer) currents, 
although the main southern current (the California current) is farther 
offshore than the northern current (the Davidson current). Humboldt Bay 
and the Klamath River are more than 260 mi (418 km) and 320 mi (515 km) 
away by sea, respectively, from the San Francisco Bay. It is impossible 
to reliably approximate how many individuals as a proportion of the 
population may be transported by currents or swim between the San 
Francisco Bay-Delta and the other estuaries.

Distinct Population Segment

    We consider a species for listing under the Act if available 
information indicates such an action might be warranted. ``Species'' is 
defined in section 3 of the Act to include any subspecies of fish or 
wildlife or plants, and any distinct vertebrate population segment of 
fish or wildlife that interbreeds when mature (16 U.S.C. 1532(16)). We, 
along with the National Marine Fisheries Service (now the National 
Oceanic and Atmospheric Administration-Fisheries (NOAA - Fisheries)), 
developed the Policy Regarding the Recognition of Distinct Vertebrate 
Population Segments (DPS Policy) (February 7, 1996; 61 FR 4721) to help 
us in determining what constitutes a DPS. Under our DPS policy, we 
consider three elements in a decision regarding the status of a 
possible DPS as endangered or threatened under the Act. These elements 
include: (1) The discreteness of the population segment in relation to 
the remainder of the species to which it belongs; (2) the significance 
of the population segment to the species to which it belongs; and (3) 
the population segment's conservation status in relation to the Act's 
standards for listing. If we determine that a population segment meets 
the discreteness and significance standards, then the level of threat 
to that population segment is evaluated based on the five listing 
factors established by the Act to determine whether listing the DPS as 
either threatened or endangered is warranted.

Discreteness

    The DPS policy states that a population 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 Act.

Significance

    Under our DPS Policy, once we have determined that a population 
segment is discrete, we consider its biological and ecological 
significance to the larger taxon to which it belongs. This 
consideration may include, but is not limited to: (1) Persistence of 
the discrete

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population segment in an ecological setting that is unusual or unique 
for the taxon; (2) evidence that loss of the discrete population 
segment would result in a significant gap in the range of the 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; or 
(4) evidence that the discrete population segment differs markedly from 
other populations of the species in its genetic characteristics.
    If a population is considered both discrete and significant (i.e., 
it is a distinct population segment) its evaluation for endangered or 
threatened status will be based on the Act's definitions of those terms 
and a five-factor analysis will be completed.

Distinct Population Segment Analysis

Discreteness
    The petitioners claim the San Francisco Bay-Delta population of 
longfin smelt is discrete because there is no evidence that large 
numbers of longfin smelt migrate between populations within their range 
in the eastern Pacific or along the California coast. Additionally, 
they cite survey data indicating longfin smelt populations within 
several hundred miles of the San Francisco Bay-Delta are small and 
possibly declining, which leads the petitioners to conclude that it is 
unlikely that longfin smelt in the San Francisco Bay-Delta are 
supplemented by immigration from other areas. Additionally, the 
petitioners cite Moyle (2002, p. 235) who concluded the longfin smelt 
in the San Francisco Bay-Delta are reproductively isolated from other 
population units.
    The range of the longfin smelt extends from Prince William Sound in 
Alaska, south to the San Francisco Bay-Delta. In California, longfin 
smelt have been found in the lower reaches and estuaries of the 
Klamath, Eel, Van Duzen (a tributary to the Eel River), and Russian 
Rivers, but populations in these areas are currently considered 
relatively small. We are unaware of historical numbers in these areas. 
Longfin smelt were historically abundant in Humboldt Bay, but this 
population is in decline (The Bay Institute et al. 2007, p. 1). The San 
Francisco Bay-Delta population is the southernmost self-sustaining 
population of longfin smelt (The Bay Institute et al. 2007, p. ii). One 
individual was found in Monterey Bay (Moyle 2002, p. 236), but a self-
sustaining population is not considered present there. See Range and 
Extant Distribution for more information.
Geographical Isolation
    The petitioners assert that the San Francisco Bay-Delta population 
is geographically isolated from all other populations, that there is no 
evidence of large numbers of longfin smelt migrating between 
populations, and that it is highly unlikely that the San Francisco Bay-
Delta population is supplemented by populations from other areas. The 
petitioners requested the Service list the San Francisco Bay-Delta 
population of the longfin smelt as a DPS. We note that standard set 
forth in the DPS policy is that a DPS be ``markedly separated'' from 
other populations--thus, while absolute separation is not required, 
neither are ``large numbers'' of individuals migrating between 
populations.
    Although the range of longfin smelt extends into Canada, the San 
Francisco Bay-Delta population is not separated from all other 
populations by an international border. Therefore, the San Francisco 
Bay-Delta population cannot be discrete due to be delimiting by an 
international border.
    We are unaware of any targeted sampling efforts for longfin smelt, 
so the information we have about their distribution and numbers and our 
conclusions outlined below have been gleaned from past and ongoing 
sampling efforts that target other aquatic organisms. The following 
outlines the survey efforts and detections of longfin smelt in 
California north of San Francisco Bay as a result of these non-target 
sampling efforts.
    In the Klamath River, longfin smelt were found in low numbers in 
the early 1990s using electrofishing techniques from river mile 2 to 
river mile 4 (river km 3.2 to 6.4). The Klamath River is located 
approximately 320 mi (515 km) by sea north of the San Francisco Bay-
Delta. Additional sampling by the Yurok Tribe in the Klamath River in 
recent years did not identify any longfin smelt; however, this sampling 
targeted salmonids and, as a result, any osmerids that may have been 
inadvertently captured were not documented (Gale 2008, p. 1). Also, 
because standard sampling methods for salmonids are likely highly 
inefficient for collecting longfin smelt, their presence or absence in 
the Klamath River cannot be determined based on the Yurok Tribe 
sampling data.
    In Humboldt Bay in Humboldt County, California, longfin smelt 
population numbers have likely always been small (Moyle 2002, p. 237). 
Humboldt Bay is located approximately 260 mi (418 km) by sea north of 
the San Francisco Bay-Delta. A total of 12 longfin smelt were caught in 
north Humboldt Bay during surveys using a variety of gear types from 
2003 to 2005 (Pinnix et al. 2005, p. 11), and one adult was netted in 
Freshwater Creek (a tributary to Humboldt Bay) in February 2008 (Justin 
Garwood 2008, p. 1). Eleven longfin smelt were found at a total of four 
sites in Humboldt Bay between 2000 to 2001 (Cole 2004, p. 20). Survey 
efforts conducted by California State University at Humboldt caught 
only about half a dozen longfin smelt in Humboldt Bay in the past 10 
years of non-target sampling using both trawls and beach seines 
(Mulligan 2008, p. 1). In addition, non-target sampling around a dredge 
disposal site about 2 mi (3.2 km) offshore from Humboldt Bay yields an 
average of a few dozen longfin smelt every year (Mulligan 2008, p. 1).
    The Humboldt Bay tributaries of Hookton Slough, Salmon Creek, and 
Elk River Slough were sampled from 2005 to 2006, and Freshwater/Eureka 
Slough and its tributaries were sampled from 2003 to 2006. Longfin 
smelt were found in very low numbers during these years in all of these 
tributaries (Mike Wallace, 2008, p. 1). Spawning longfin smelt have 
been recorded in the Van Duzen River and in the Eel River drainage in 
Humboldt County (Moyle 2002, p. 235), but the current status of longfin 
smelt and sampling efforts in these rivers is unknown. Humboldt Bay and 
the Klamath River estuaries may also support small but self-sustaining 
populations of longfin smelt. Pre-spawn and spent (post-spawn) adults 
have been detected in the Klamath River estuary as recently as 2001, 
and adult and juvenile longfin smelt have been detected in recent years 
in Humboldt Bay, suggesting spawning and recruitment may be occurring 
in these estuaries (Baxter 2008, p. 1).
    In the Russian River in Sonoma County, California (from the river 
mouth to approximately 10 mi (16 km) upriver), low numbers of longfin 
smelt were caught using otter trawls from 1997 to 2000 (Sonoma County 
Water Agency (SCWA) 1999, Appendices B-4 and B-8; SCWA 2000, Appendices 
B-8, B-10, B-11, and B-12; SCWA 2001, pp. 18-19). The Russian River 
estuary is approximately 75 mi (120 km) by sea north of the San 
Francisco Bay-Delta. No longfin smelt were caught in the Russian River 
using beach seines between 2003 and 2007 (SCWA 2004, p. 7; SCWA 2005, 
pp. 7-8; SCWA 2006, pp. 10-11; Cook 2008, p. 1). However, it is likely 
that beach seining is an ineffective method for determining presence or 
absence of longfin smelt,

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because it does not sample the depths (typically 15 to 22 feet (ft) (4 
to 7 meters (m)) or the middle of the river channel where longfin smelt 
were previously found in the Russian River using otter trawls.
    One individual longfin smelt was found in Abbotts Lagoon at Point 
Reyes National Seashore in 1999 (Saiki and Martin 2001, p. 128), and 
near-shore midwater trawl surveys conducted by the NOAA - Fisheries in 
the spring for juvenile rockfish also detected longfin smelt and other 
smelt not identified to species at several locations from Cyprus Point 
near Monterey Bay to Point Reyes near Bodega Bay in 1984, 1994, and 
2001 (Baltz, 2008, pp. 1-32). Although sampling continues, smelts 
caught have not been identified to species since 2001, and many of the 
stations where longfin smelt were identified in the 1980s and 1990s 
near the Gulf of the Farallones have not been sampled since 1996 
(Sakuma, 2008, p. 1).
    The City of San Francisco detected longfin smelt a few miles 
offshore in the Pacific Ocean in 1983 and 1984, suggesting that 
individuals from the San Francisco estuary disperse beyond the Golden 
Gate Bridge (City of San Francisco 1985, pp. 5-8; Rosenfield and Baxter 
2007, p. 1590). Additional surveys conducted between 1987 and 2007 were 
not examined for pelagic fish species, so it is possible that longfin 
smelt were captured but not identified during these surveys (Kellogg 
2008, p. 1).

Summary of Geographic Isolation

    Although no physical barriers exist between the San Francisco Bay-
Delta and estuarine habitat to the north, the distance that longfin 
smelt are able to travel out into the open ocean or northward along the 
coast to reach these areas is unknown. The 1995 Sacramento/San Joaquin 
Delta Native Fishes Recovery Plan (Service 1995, pp. 47-65) states that 
the San Francisco estuary population ``is isolated from other 
populations.'' However, as described above in the Range and Extant 
Distribution section, it is likely that longfin smelt are moving or 
being transported via currents between the San Francisco Bay-Delta 
estuary and other estuaries to the north. A recent review of the 
abundance and distribution of longfin smelt within the San Francisco 
Bay-Delta concluded that at least a portion of the longfin smelt 
population within the San Francisco Bay-Delta is anadromous and 
routinely disperses outside the San Francisco Bay-Delta estuary and 
into the Pacific Ocean (Rosenfield and Baxter 2007, p. 1590). Although 
we know of no studies assessing swimming ability of longfin smelt, it 
may be comparable to juvenile salmon, which have the capability to swim 
back into estuaries from the ocean (Moyle 2008, p. 1). Based on the 
recent information that a portion of the San Francisco Bay-Delta 
population of longfin smelt are anadromous and able to swim into and 
out of the San Francisco Bay-Delta, it is likely that individuals have 
the ability to swim into and out of ocean currents and into and between 
estuaries, including estuaries outside of the San Francisco Bay-Delta 
estuary. In addition, other individuals may be transported by other 
mechanisms, such as high outflows and ocean currents (see Range and 
Extant Distribution section). The distance that longfin smelt could 
swim or be transported from the San Francisco Bay-Delta is unknown. It 
is possible that the San Francisco Bay-Delta population is 
supplementing smaller nearby estuaries (such as the Russian River); 
therefore, Moyle's (2002, p. 235) conclusion that longfin smelt in the 
San Francisco Bay-Delta being reproductively isolated is questionable. 
Additionally, it is possible that other self-sustaining estuaries (such 
as Humboldt Bay, Coos Bay, Columbia River) may be supplementing smaller 
estuaries in their vicinities. Therefore, we have determined the San 
Francisco Bay-Delta population of longfin smelt is not geographically 
isolated from other longfin smelt populations.

Genetic Separation

    The petitioner states that the San Francisco Bay-Delta population 
of longfin smelt differs genetically from a population in Lake 
Washington in Washington State (Stanley et al. 1995, pp. 390-396). The 
petitioners conclude from the single study that the San Francisco Bay-
Delta population differs markedly from other populations genetically 
and that additional genetic analysis will confirm that the San 
Francisco Bay-Delta population represents an evolutionarily independent 
lineage of this species and qualifies as a DPS.
    Only one genetic study has addressed longfin smelt. Stanley et al. 
(1995, pp. 390-396) used electrophoresis of allozymes to examine 
genetic variation within and between two populations of longfin smelt. 
Allozymes are proteins used as genetic markers and have been used to 
assess genetic variation for many years. Allozyme studies have the 
advantage of being relatively inexpensive and straightforward, once the 
basic technique is developed for a group. However, drawbacks of using 
electrophoretic allozyme studies include the limited number of proteins 
that can be screened (Parker et al. 1998, pp. 362-363) and the fact 
that they often detect little variability (Haig 1998, p. 419). It is 
not uncommon for population biologists to encounter species for which 
allozymes cannot be used as genetic markers because they lack variation 
(Parker et al. 1998, pp. 362-363).
    Stanley et al. (1995, p. 395) found the San Francisco Bay-Delta 
population and Lake Washington populations of longfin smelt were 
significantly different in allele frequencies at several loci (gene 
locations). However, the authors also stated the overall genetic 
dissimilarity was within the range of other conspecific fish species 
(Stanley et al. 1995, p. 395) and concluded their research indicates 
longfin smelt from Lake Washington and the San Francisco Bay-Delta are 
conspecific (of the same species) despite the large geographic 
separation. We believe that this study is not well suited to address 
whether the San Francisco Bay-Delta longfin smelt population is 
markedly separated from other populations of longfin smelt (the 
criterion of the DPS policy) because only two locations were sampled. 
These two locations are ecologically different from one another and 
widely separated geographically. The life history and ecology of the 
landlocked Lake Washington longfin smelt population is different than 
other estuary populations, and may have been geographically separated 
for many years from other populations with access to the open ocean. A 
more appropriate comparison would have been to analyze longfin smelt 
from a series of locations with access to the open ocean (e.g., 
Columbia River to Humboldt Bay) to assess the potential of genetic 
relatedness of longfin smelt from the San Francisco Bay-Delta and other 
populations. While the study indicates that Lake Washington and San 
Francisco Bay-Delta longfin smelt differ significantly at some allozyme 
loci, it does not evaluate the genetic relationship between these 
populations and intervening populations along the Pacific coast.
    Furthermore, at the time of their study, the authors believed the 
longfin smelt in Humboldt Bay to be rare or extinct but did acknowledge 
the existence of longfin smelt from the Klamath River, approximately 
124 mi (200 km) north of Humboldt Bay. Stanley et al. (1995, p. 395) 
surmised that if the Humboldt Bay population was extinct, then genetic 
exchange between the Delta and Klamath River would be extremely 
unlikely. This line of reasoning appears to imply geographic isolation. 
However, based on more recent occurrence information, as

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we have outlined above, longfin smelt are found in estuaries north of 
the San Francisco Bay-Delta, including the Russian River, Humboldt Bay, 
and the Klamath River. Also taking into account recent confirmation 
that a portion of the San Francisco Bay-Delta population of longfin 
smelt is fully anadromous and able to swim into and out of the San 
Francisco Bay-Delta, and that it is likely that individuals have the 
ability to swim into and out of ocean currents and into and between 
estuaries, including estuaries outside of the San Francisco Bay-Delta 
estuary, we believe the potential for genetic interchange exists.
    As mentioned above, research to evaluate any genetic differences 
between the San Francisco Bay-Delta longfin smelt and other coastal 
longfin smelt populations has not yet been completed. There is also no 
indication that longfin smelt differ morphologically between the San 
Francisco Bay-Delta population and other populations. Researchers from 
University of California at Davis have undertaken a study using more 
modern molecular techniques, which examines DNA directly rather than 
looking at the product derived from DNA (i.e., proteins) to determine 
genetic variability within and among populations in Northern 
California, Oregon, and Washington (May 2008, p. 1). Additional study 
should provide more information on the distribution of genetic 
variation within the species and determine if longfin smelt from 
different locations are intermixing. We believe that while this 
additional study is needed, at this time we can not conclude that San 
Francisco Bay-Delta longfin smelt differ markedly from other 
populations in its genetic characteristics. Therefore, we have 
determined that, based on the best scientific and commercial 
information available, the San Francisco Bay-Delta population is not 
genetically distinct from other populations of longfin smelt.

Determination of Discreteness

    Our DPS policy requires that when determining whether a population 
meets the definition of being a DPS, we must first consider 
discreteness of the population segment in relation to the remainder of 
the species to which it belongs. The population must be markedly 
separated from other population of the taxon as a consequence of 
physical, physiological, ecological, behavioral, genetic or 
morphological factors or as a result of international boundaries where 
significant differences in exploitation, management, conservation 
status, or regulatory mechanisms exist. If a population is considered 
discrete then we would consider the biological and ecological 
significance of the population. To be considered a DPS under our 
policy, the population must meet both the discreteness and significance 
aspects of the policy.
    We have determined that, based on the best scientific and 
commercial information available, the San Francisco Bay-Delta 
population of the longfin smelt is not markedly separated from the 
other populations of longfin smelt. The only available data to address 
the markedly separate standard for longfin smelt relate to geographic 
isolation and genetic uniqueness, and we do not find that these data 
indicate longfin smelt from the San Francisco Bay-Delta are markedly 
separated from other longfin smelt found elsewhere. Recent studies 
indicate that at least part of the San Francisco Bay-Delta population 
is anadromous and able to swim into and out of estuaries. Individuals 
may also be carried by currents from the San Francisco Bay-Delta to 
other estuaries outside the San Francisco Bay-Delta which leads us to 
the conclusion that longfin smelt may be able to disperse between 
populations. Although it is impossible without further study to 
reliably approximate how many individuals are being transported or 
swimming between the San Francisco Bay-Delta and the other estuaries, 
``large numbers'' of migrating individuals are not required to rule out 
populations being markedly separated. Nor is absolute isolation 
required for populations to be markedly separated. On balance, the 
limited data available do not suggest that the San Francisco Bay-Delta 
population of the longfin smelt is markedly separate from populations 
outside the San Francisco Bay-Delta. In addition, the only genetic 
study conducted to date examined only Lake Washington and San Francisco 
Bay-Delta longfin smelt, a sampling scheme too limited to reasonably 
address whether longfin smelt in the San Francisco Bay-Delta differ 
genetically from other locations along the Pacific coast. Therefore, we 
have determined that the San Francisco Bay-Delta population of longfin 
smelt is not discrete as defined under our DPS policy.

Significance

    Since the San Francisco Bay-Delta population of longfin smelt is 
not discrete as defined under our DPS policy, we do not need to 
evaluate the significance of the population to the species as a whole.

Finding

    We have carefully assessed the best scientific and commercial 
information available regarding whether the San Francisco Bay-Delta 
population of the longfin smelt is a distinct population segment. We 
have reviewed the petition, information available in our files, and all 
information submitted to us following our 90-day petition finding (73 
FR 24911, May 6, 2008). We also consulted with recognized smelt 
experts, including State and Federal agency biologists, academics, and 
individuals involved in sampling and surveying efforts for the longfin 
smelt.
    We find the San Francisco Bay-Delta population of the longfin smelt 
does not meet the discreteness criterion of our DPS policy (and 
therefore we did not undertake a significance review) and therefore is 
not a valid DPS. As a result, the San Francisco Bay-Delta population of 
the longfin smelt is not a listable entity under the Act and we will 
not complete a 5-factor analysis of the San Francisco Bay-Delta 
population of the longfin smelt in response to the August 8, 2007, 
petition. This finding is based on information obtained on the 
potential for dispersal via ocean currents, and on information that a 
portion of the longfin smelt within the San Francisco Bay-Delta 
regularly disperse out to the Pacific Ocean and are fully anadromous. 
Once individuals emigrate from the San Francisco Bay Estuary they are 
likely transported by ocean currents and able to occupy estuaries 
outside of the San Francisco Bay-Delta for an undetermined amount of 
time.
    However, given the demonstrated anadromy of the San Francisco Bay 
Estuary population of longfin smelt and its potential for dispersal, we 
are initiating a range wide status assessment of the longfin smelt and 
are seeking information regarding: taxonomy, genetics, distribution, 
habitat selection, population density and trends, habitat trends, 
effects of management, dispersal and migratory capabilities or patterns 
of dispersal, and potential threats to the longfin smelt throughout its 
range in Alaska, Canada, Washington, Oregon, and California. Upon 
completion of this review, we will also evaluate whether the best 
available scientific information suggests that the San Francisco Bay-
Delta population of the longfin smelt may be considered to occupy a 
significant portion of the range (SPR), and institute appropriate 
action. We encourage interested parties to continue to gather data that 
will assist in determining the status of the longfin smelt. New 
information should be

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submitted to the Field Supervisor, Sacramento Fish and Wildlife Office 
(see ADDRESSES).

References Cited

    A complete list of all references cited in this proposal is 
available upon request. You may request a list of all references cited 
in this document from the Supervisor, Sacramento Fish and Wildlife 
Office (see ADDRESSES).

Author

    The primary authors of this notice are staff members of the 
Sacramento Fish and Wildlife Office, U.S. Fish and Wildlife Service, 
2800 Cottage Way, Sacramento, CA 95825.

Authority

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

    Dated: March 31, 2009.
Rowan W. Gould,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. E9-8087 Filed 4-8-09; 8:45 am]
BILLING CODE 4310-55-S