[Federal Register: August 4, 2008 (Volume 73, Number 150)]
[Page 45238-45240]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]



Fish and Wildlife Service

[FWS-R9-FHC-2008-N0185; 71490-1351-0000-M2]

Marine Mammal Protection Act; Stock Assessment Reports

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of availability of final revised marine mammal stock 
assessment reports for three stocks of northern sea otters in Alaska; 
response to comments.


SUMMARY: In accordance with the Marine Mammal Protection Act (MMPA), 
the Fish and Wildlife Service (Service) has incorporated public 
comments into revisions of marine mammal stock assessment reports for 
the three stocks of northern sea otters (Enhydra lutris kenyoni) in 
Alaska. The 2008 final stock assessment reports are now complete and 
available to the public.

ADDRESSES: Send requests for printed copies of the final stock 
assessment reports to: Chief, U.S. Fish and Wildlife Service, Marine 
Mammals Management Office, 1011 East Tudor Road, Anchorage, AK 99503; 
(800) 362-5148. Copies of the final revised stock assessment reports 
are also available on the Internet in Adobe Acrobat format at http://

SUPPLEMENTARY INFORMATION: One of the goals of the MMPA (16 U.S.C. 
1361-1407) is to ensure that stocks of marine mammals occurring in 
waters under the jurisdiction of the United States do not experience a 
level of human-caused mortality and serious injury that is likely to 
cause the stock to be reduced below its optimum sustainable population 
level (OSP). OSP is defined as `` * * * the number of animals which 
will result in the maximum productivity of the population or the 
species, keeping in mind the carrying capacity of the habitat and the 
health of the ecosystem of which they form a constituent element.''
    To help accomplish the goal of maintaining marine mammal stocks at 
their OSPs, section 117 of the MMPA requires the Service and the 
National Marine Fisheries Service (NMFS) to prepare stock assessment 
reports for each marine mammal stock that occurs in waters under the 
jurisdiction of the United States. These stock assessments are to be 
based on the best scientific information available and are, therefore, 
prepared in consultation with established regional scientific review 
groups. Each stock assessment must include:
    (1) A description of the stock and its geographic range; (2) 
minimum population estimate, maximum net productivity rate, and current 
population trend; (3) estimate of human-caused mortality and serious 
injury; (4) commercial fishery interactions; (5) status of the stock; 
and (6) potential biological removal level (PBR). The PBR is defined as 
`` * * * the maximum number of animals, not including natural 
mortalities, that may be removed from a marine mammal stock while 
allowing that stock to reach or maintain its OSP.'' The PBR is the 
product of the minimum population estimate of the stock 
(Nmin); one-half the maximum theoretical or estimated net 
productivity rate of the stock at a small population size 
(Rmax); and a recovery factor (Fr) of between 0.1 
and 1.0, which is intended to compensate for uncertainty and unknown 
estimation errors.
    Section 117 of the MMPA also requires the Service and the NMFS to 
review and revise the stock assessment reports: (a) At least annually 
for stocks that are specified as strategic stocks; (b) at least 
annually for stocks for which significant new information is available; 
and (c) at least once every 3 years for all other stocks.
    A strategic stock is defined in the MMPA as a marine mammal stock: 
(A) For which the level of direct human-caused mortality exceeds the 
PBR; (B) which, based on the best available

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scientific information, is declining and is likely to be listed as a 
threatened species under the Endangered Species Act of 1973 (ESA) 
within the foreseeable future; or (C) which is listed as a threatened 
or endangered species under the ESA, or is designated as depleted under 
the MMPA.
    Draft 2008 stock assessment reports for the 3 Alaska stocks of 
northern sea otters were made available for a 90-day public review and 
comment period on February 6, 2008 (73 FR 6994). Prior to releasing 
them for pubic review and comment, the Service subjected the draft 
reports to internal technical review and to scientific review by the 
Alaska Regional Scientific Review Group established under the MMPA. 
Following the close of the comment period, the Service revised the 
stock assessments and prepared the final 2008 stock assessment reports.
    We revised these final stock assessment reports based on public 
comments received (see below). The status of each stock remained 
unchanged from the draft revised SARs that were provided for public 
comment, and with the exception of the southwest Alaska stock, PBR 
levels were not changed. Estimates of fishery-related mortality and 
serious injury have been revised for all three stock assessment 
reports. We addressed responses to most of the public comments by 
adding new text for clarity.
    A summary of the final revised stock assessment reports is 
presented in Table 1. The table lists each stock's Nmin, 
Rmax, Fr, PBR, annual estimated human-caused 
mortality and serious injury, and status.

                           Table 1--Summary of Final Revised Stock Assessment Reports for Three U.S. Northern Sea Otter Stocks
                                                                                             Annual 5-year estimated human-
                                                                                 Serious            caused mortality
               Stock                   NMIN       RMAX        FR        PBR       injury  ------------------------------------        Stock status
                                                                                               Fishery/other      Subsistence
Northern sea otters (Southeast AK)      9,136       0.20        1.0        914          0  Unknown..............         322   Non-strategic
Northern sea otters (Southcentral      12,774       0.20        1.0      1,277          0  Unknown..............         346   Non-strategic
Northern sea otters (Southwest AK)     38,703       0.20        0.1        387          0  <10..................          91   Strategic

Comments and Responses

    The Service received 3 comments on the drafts stock assessment 
reports. The issues raised in those comments and our responses are 
provided below.
    Comment 1: The use of a recovery factor of 0.25 for the southwest 
Alaska stock is too high; a recovery factor of 0.1 should be used 
    Response: The choice of recovery factors for population stocks that 
are declining is complex. The southwest Alaska stock is currently 
listed as threatened under the ESA and the current population trend is 
one of decline. Therefore, we agree with this comment to take a more 
conservative approach and have reduced the recovery factor for the 
southwest Alaska stock to 0.1, which lowers the PBR to 387.
    Comment 2: Given that one otter was self-reported by the fisher to 
have been caught in a trawl fishery, the conclusion that ``estimated 
level of incidental motality and serious injury associated with Alaska 
trawl, longline, and pot groundfish fisheries is zero'' is not 
    Response: Available information on this self-reported incident is 
unclear whether the otter was caught and killed in the trawl fishery, 
or was a dead animal that was simply caught by the trawl. The text of 
the southwest Alaska stock assessment has been revised to say that the 
``estimated level of incidental morality and serious injury associated 
with Alaska trawl, longline, and pot groundfish fisheries averages less 
than one animal per year.''
    Comment 3: The estimate that mortality and serious injury in the 
Kodiak salmon set net fishery is less than one animal per year is not 
    Response: This section of the southwest Alaska stock assessment 
report has been revised to indicate that the level of mortality and 
serious injury rate for this fishery is likely no more than 10 animals 
per year.
    Comment 4: Information is insufficient to conclude that fishery 
impacts on the southcentral and southeast Alaska stocks is 
insignificant and approaching a zero mortality rate.
    Response: We have revised the southcentral and southeast Alaska 
stock assessment reports to more accurately characterize the 
uncertainties in the level of fishery mortality and serious injury.
    Comment 5: The Service should update stock assessment reports on 
the schedule specified under section 117 of the MMPA.
    Response: The Service will continue to review available information 
on an annual basis and revise stock assessment reports for the northern 
sea otter in Alaska as appropriate.
    Comment 6: The Service should review available information on sea 
otter stock structure in Alaska.
    Response: Information on stock structure is driven primarily by 
genetic analysis of tissue samples. The most recent study of this 
nature was conducted in 2002. Since that time, more sample material has 
been collected during live-capture studies in the Kodiak archipelago 
(southwest Alaska stock) and Kamishak Bay (southcentral Alaska stock). 
Additional tissue samples from other areas are required, especially 
Kamishak Bay and the Alaska Peninsula adjacent to Shelikof Strait, 
before sea otter stock structure in Alaska can be analyzed.
    Comment 7: Methods used to estimate sea otter abundance are not 
adequately described.
    Response: The methods used to estimate sea otter abundance are 
thoroughly described in the references used to prepare these stock 
assessment reports. We believe it is redundant to describe them more 
comprehensively in the stock assessment reports.
    Comment 8: Description of fishery interactions is incomplete; the 
stock assessment reports should list all fisheries known to interact 
with sea otters.
    Response: We have included the relevant fisheries from the NOAA--
Fisheries ``List of Fisheries'' that had previously been incorporated 
by reference.
    Comment 9: Stock assessment reports do not adequately consider 
possible interactions in fisheries that are not

[[Page 45240]]

observed or where observer coverage is low.
    Response: The predominant type of fishing gear that has been known 
to interact with sea otters are salmon set and drift gillnets. 
Available information suggests that fisheries using other types of 
gear, such as trawl, longline, pot, and purse seine appear to be less 
likely to have interactions with sea otters due to either the areas 
where such fisheries operate, or the specific gear used, or both. 
Gillnet fisheries occur throughout the range of sea otters in Alaska; 
however, the nature of their potential for interaction depends on 
several factors including sea otter distribution and abundance relative 
to the distribution and effort expended in these fisheries. We believe 
that application of entanglement rates derived from small sample sizes 
in observed fisheries to unobserved fisheries in other areas would 
produce questionable results.
    Comment 10: Stock assessment reports do not consider other impacts 
from oil and gas development besides oil spills.
    Response: We considered disturbance from oil and gas exploration, 
development, and production in the draft stock assessments; however, we 
did not state this point explicitly in the draft stock assessment 
reports. We have revised the final stock assessment reports 
    Comment 11: Fuel oil spills from ship traffic should be considered 
for the southcentral and southeast Alaska stocks.
    Response: We have included additional information from the Alaska 
Department of Environmental Conservation spill reporting database about 
ship traffic and other sources that have resulted in discharges of 
crude and noncrude oil into the marine environment for all 3 stock 
assessment reports.
    Comment 12: The stock assessment reports should describe the 
reasons for and implications of the age/sex distribution of the 
subsistence harvest on the demography and dynamics of sea otter 
    Response: We believe the suggested additional in-depth analysis of 
the subsistence harvest is beyond the scope of these reports as it 
relates to determining the status of the stocks.
    Comment 13: The impact of other factors, such as contaminants, 
should be evaluated.
    Response: Available information is insufficient to quantitatively 
estimate the impacts of these factors.
    Comment 14: Additional detail on the Unusual Mortality Event should 
be included in the stock assessment reports.
    Response: Studies of sea otter disease, mortality, and survival are 
ongoing. Results are not yet available for inclusion in this stock 
assessment report.
    Comment 15: Given the dates of the various surveys used to estimate 
the population size of the southwest Alaska stock, the current 
population may be lower than the estimated value.
    Response: We acknowledge that population estimates for some of the 
regions within the southwest Alaska stock are somewhat dated; however, 
they are the best available scientific information at this time. 
Population monitoring for this stock is an important component of the 
recovery plan that is in development. As this stock is listed as 
threatened under the ESA, it is considered strategic under the MMPA and 
subject to annual review, regardless of the actual population size.
    Comment 16: Apparent regional population trends in the southeast 
Alaska stock should be discussed in greater detail.
    Response: The U.S. Geological Survey collected survey information 
for the southeast Alaska stock. A summary report that addresses this 
issue is in preparation; however, conclusions are not available at this 
    Comment 17: Information gathered from the fishing industry cannot 
be relied upon for truthfulness or accuracy because of their concern 
for profits.
    Response: The Service relied on the best available scientific 
information in the preparation of these stock assessment reports, and 
readily acknowledges the limitations of these data. Although some of 
the information is self-reported, we also rely on fisheries observer 
programs when available.
    Comment 18: The agency's system for observing the catch is 
incorrect and untruthful. Cameras on boats and fines and jail times are 
    Response: Observer programs are conducted by the National Marine 
Fisheries Service of the Department of Commerce. We have forwarded 
these suggested improvements to them for consideration.
    Comment 19: The words ``optimum sustainable population'' are 
opposed as the phrase promotes overutilization of the wildlife.
    Response: The term ``Optimal Sustainable Population'' is defined in 
the Marine Mammal Protection Act (16 U.S.C. 1362).

References Not Cited in the Notice of Availability of Draft Revised 

Manly, B.F.J. 2006. Incidental catch and interactions of marine 
mammals and birds in the Cook Inlet salmon driftnet and setnet 
fisheries. Western EcoSystems Technology Inc. Report. Cheyenne, 
Wyoming, USA. 98pp.
Manly, B.F.J. 2007. Incidental take and interactions of marine 
mammals and birds in the Kodiak Island salmon set gillnet fishery, 
2002 and 2005. Western EcoSystems Technology Inc. Report. Cheyenne, 
Wyoming, USA. 221pp.

    Authority: The authority for this action is the Marine Mammal 
Protection Act of 1972, as amended (16 U.S.C. 1361-1407).

    Dated: July 29, 2008.
Rowan W. Gould,
Acting Director, Fish and Wildlife Service.
[FR Doc. E8-17804 Filed 8-1-08; 8:45 am]