[Federal Register Volume 60, Number 192 (Wednesday, October 4, 1995)]
[Notices]
[Pages 52008-52012]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-24622]



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DEPARTMENT OF THE INTERIOR

Marine Mammals; Stock Assessment Reports

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of completion and availability of final marine mammal 
stock assessments and guidelines for preparing stock assessments.

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SUMMARY: Section 117 of the 1994 amendments to the Marine Mammal 
Protection Act (MMPA) requires the Fish and Wildlife Service (Service) 
and the National Marine Fisheries Service (NMFS) to prepare stock 
assessments for each marine mammal stock that occurs in waters under 
the jurisdiction of the United States. The Service made draft stock 
assessments and preliminary guidelines available for public review and 
comment on August 23, 1994. Comments received from the public and from 
scientific review groups (established according to section 117) were 
reviewed and incorporated into the reports and guidelines, as 
appropriate. Final stock assessments have been completed and are now 
available for polar bears, walrus, and northern sea otters in Alaska; 
southern sea otters in California and northern sea otters in Washington 
State; and two West Indian manatee stocks in the southeastern United 
States and Puerto Rico. Final guidelines for preparing these stock 
assessments are also available.

ADDRESSES: Copies of these final stock assessments and final guidelines 
are available from the Division of Fish and Wildlife Management 
Assistance, U.S. Fish and Wildlife Service, Mail Stop 840-ARLSQ, 1849 C 
Street NW., Washington, D.C. 20240.

FOR FURTHER INFORMATION CONTACT: Jeff Horwath, Division of Fish and 
Wildlife Management Assistance, Arlington, Virginia, at 703/358-1718. 
For specific information about stock assessments for polar bears, 
walrus, and northern sea otters in Alaska, contact David McGillivary in 
the Service's Office of Marine Mammals Management, Anchorage, Alaska, 
at 907/786-3800. For specific information about stock assessments for 
southern sea otters in California and northern sea otters in Washington 
State, contact Carl Benz in the Service's field office in Ventura, 
California, Telephone 805/644-1766. For specific information about 
stock assessments for West Indian manatees in the southeastern United 
States and Puerto Rico, contact Robert Turner in the Service's field 
office in Jacksonville, Florida, Telephone 904/232-2580.

SUPPLEMENTARY INFORMATION: On April 30, 1994, the MMPA Amendments of 
1994 were enacted into law (Public Law 103-238). New section 117 of the 
MMPA required the Service and the NMFS (as appropriate) to prepare and 
periodically revise stock assessments for marine mammals that occur in 
waters 

[[Page 52009]]
under the jurisdiction of the United States. These reports must contain 
information regarding the distribution and abundance of the stocks, 
population growth rates and trends, estimates of annual human-caused 
mortality from all sources, descriptions of the fisheries with which 
the stocks interact, and the status of each stock.
    Although many of the items included in the reports were described 
explicitly in the MMPA, many elements, including a quantitative 
definition of the parameters used in calculating Potential Biological 
Removal (PBR) levels, were defined only in general terms. To promote 
consistent interpretation of the provisions of the law, the NMFS 
convened a workshop composed of NMFS and FWS scientists in June 1994 to 
develop preliminary guidelines to be used in preparing draft stock 
assessments.
    On August 23, 1994, the Service published in the Federal Register a 
notice of availability of draft guidelines and stock assessments (59 FR 
43353) for polar bears, Pacific walrus, and Alaska sea otters in 
Alaska, southern sea otters in California and northern sea otters in 
Washington State, and West Indian manatees in the southeastern United 
States and Puerto Rico. A 90-day public comment period expired on 
November 21, 1994. Substantial background information was provided in 
that notice, and is not repeated at this time. On November 16, 1994, 
the Service, in response to public concerns, extended the public 
comment period through December 1, 1994 (59 FR 59243). This new 
expiration date provided several additional days for public comment 
while reducing public confusion by aligning the Service's cut-off date 
with that of the NMFS; that agency was developing their own stock 
assessments and had also extended their comment period to December 1, 
1994. The Service also concluded that it would allow a reasonable 
amount of time for the Alaska Scientific Review Group (see next two 
paragraphs) to review public comments prior to the Group's scheduled 
meeting of December 12-13, 1994.
    In addition to the requirements to develop stock assessments, 
section 117 of the amendments to the MMPA also required the NMFS, in 
consultation with the Service and others, to establish three 
independent regional Scientific Review Groups (SRG) representing 
Alaska, the Pacific Coast (including Hawaii), and the Atlantic Coast 
(including the Gulf of Mexico). These SRG's were charged with providing 
advice on the stock assessments and other issues appropriate for 
pursuing the goals of the MMPA.
    Subsequent to the close of the comment period for the draft stock 
assessments, the Service provided copies of public comments, as 
appropriate, to members of the Alaska, Pacific, and Atlantic SRG's for 
review and consideration. All public comments and the input of the 
appropriate SRG's was considered by the Service in producing the final 
stock assessments announced by this Federal Register notice. Final 
guidelines have also been completed. Following is a brief summary of 
comments received and the Service's response to those comments.

Comments

Polar Bear

    Multiple stock assessment versus single stock assessment. Comment: 
Public comment favored development of two independent stock assessments 
versus one combined stock assessment for both the Beaufort Sea and 
Chukchi/Bearing Seas stocks. Response: The Service agrees and has 
recognized the information on the two stocks contained in the initial 
draft stock assessment into two individual final stock assessments.
    Minimum population estimate. Comment: Public comment was not 
received on the minimum population estimate for the Beaufort Sea stock 
or lack of an estimate for the Chukchi/Bearing Seas stock. However, a 
reanalysis of Service/National Biological Service mark and recapture 
data for the Beaufort Sea stock resulted in a revised N(min) 
estimate of 1,717 animals.
    Maximum productivity rates. Comment: One organization, and an 
observer at the Alaska SRG commented that the initial R(max) value 
of 10 percent was greater than observed rates and suggested that a 
review of data used for the calculation be conducted. Response: The 
R(max) from the draft stock assessment was revised based on 
modeling of observed reproduction and survival rates for polar bears in 
the Beaufort Sea stock. A 6 percent value is now used.
    Mortality. Comment: Several commenters suggested that the Service 
should present the harvest averages for the last 5-year period instead 
of the longer-term averages. Response: The Service concurs and has 
modified the stock assessments accordingly. A common concern was that 
modeling the effects of mortality did not account nor make adjustment 
for the skewed sex ratio of the harvest. The final estimate of the 
Potential Biological Removal (PBR) level for the Beauford Sea stock 
includes the appropriate adjustment for the sex of harvested animals.
    Status of stock. Comment: One comment stated that polar bear stocks 
in Alaska should be designated as ``strategic'' because of the lack of 
information regarding population size and status, inherently low 
reproductive capability, and threats emanating from the harvest rates 
and industry. Response: The Service has concluded that the stocks are 
``non-strategic.'' The rationale for these decisions are described in 
detail within the stock assessment and the calculations of PBR.

Pacific Walrus

    Minimum population estimate. Comment: Several groups believed this 
estimate should be based on the estimated population size obtained 
during the last range-wide aerial survey (1990). They pointed out the 
survey was conducted during an ice minimum period when only a few 
walrus were counted along the ice edge. While many walrus were counted 
on land, presumably many more were in the water and were not counted. 
Response: The stock assessment report follows guidelines outlined in 
the NMFS Workshop Report to use the best available scientific 
information to calculate the minimum population estimate, (Nmin), 
not the total estimated population, (Nbest). The minimum estimate 
obtained is based on a sum of the direct counts of the walrus observed 
on land, plus the adjusted estimate of that portion of the population 
observed on the ice.
    Maximum productivity rates. Comment: Several groups suggested the 
0.06 value for Rmax in the draft stock assessment was too low; one 
group believed it to be too high. Response: Commenting groups typically 
confused the term maximum net productivity, as defined by the amended 
MMPA and the PBR Workshop, with maximum productivity. The available 
data for maximum growth at a small population size for the Pacific 
walrus are scant. Estimated values of Rmax derived from population 
models are equivocal. In our reassessment, the Service consulted with 
experts from several agencies and the Alaska SRG. Recognizing the 
limitations of the best available data and that the Rmax value 
proposed in the draft stock assessment may not fully account for a 
skewed sex ratio in the population, the Service chose to follow the 
recommendation of the Alaska SRG to tentatively adopt 0.08 as a more 
plausible estimate of Rmax. The Service is in the process of 
reviewing available information and is open to revision of 

[[Page 52010]]
this value when and if it becomes appropriate.
    Mortality. Comment: Several groups questioned the use of 
calculating the estimated average annual mortality due to subsistence 
harvest on the basis of a 30 year data set. Some groups believed the 
estimate of struck and lost was too high. Response: The Service agrees 
that using the most recent 5-year period to calculate average annual 
mortality is an approach which more accurately reflects current harvest 
trends and levels; the value was recalculated using new information 
from Russian colleagues obtained since publication of the draft stock 
assessment. While the available information on struck and lost rates is 
somewhat dated (collected during the late 1960's-early 1970's), it is 
the only sound scientific information collected to date. The Service 
believes it is appropriate to use these data until such time as newer 
scientifically rigorous data can be obtained.
    Status of stock. Comment: Several groups objected to the draft 
stock assessment's categorization of the Pacific walrus stock as 
``strategic.'' Response: Using the new, updated, and adjusted 
information discussed above and presented in the final stock 
assessment, the Service has concluded the stock is ``non-strategic.''

Northern Sea Otter in Alaska

    Single species focus. Comment: The stock assessment inappropriately 
focused on a single species. It should have included Alaska Natives in 
its focus. Response: The stock assessment was developed based on the 
MMPA requirements and guidance developed for all stock assessments 
which focused on the status, incidental fisheries take, and other human 
take of marine mammal species.
    Multiple stocks vs. single stock. Comment: The Service was 
inconsistent on the treatment of single versus multiple stocks. Several 
commenters suggested that sea otters should be treated as multiple 
stocks, while others agreed with a single Alaska stock. Response: The 
Service will continue to consider splitting the Alaska stock of sea 
otters into multiple stocks if the scientific data supports such a 
split.
    Minimum population estimate. Comment: Several commenters suggested 
that the minimum population estimate was too low since they believed 
that sea otter populations in Alaska have been growing rapidly. Others 
concurred with the minimum population estimate. Response: The Service 
is aware of the uncertainty of the population abundance of Alaska sea 
otters. This is based on the fact that survey results are dated and 
variable. The stock assessment followed the guidelines and used the 
best available information to calculate the minimum population 
estimate, not the total estimated population. Additional language was 
added to clarify the variability of survey results. Additionally, the 
table in the stock assessment was updated to include more recent data 
that had become available.
    Potential Biological Removal. Comment: Commenters suggested that 
the Potential Biological Removal level should not be determined because 
of the uncertainty associated with the minimum population estimate and 
the lack of current survey information. Response: See ``Minimum 
population estimate'' discussion above.
    Maximum productivity rate. Comment: Several commenters suggested 
that the maximum productivity rate was too high, while another believed 
it to be accurate. Response: After reviewing public comments and the 
comments of the Alaska Scientific Review Group, the maximum 
productivity rate was increased to 20 percent based on information in 
the scientific literature.
    Incidental take. Comment: Comments were received describing the 
incidental take of sea otters by commercial fisheries as insignificant, 
while another commenter suggested that our incidental take data was 
inadequate to evaluate commercial fishery interactions. Response: The 
best available information was used by the Service. If more information 
becomes available, future stock assessments will be modified 
accordingly.
    Native harvest. Comment: One commenter believed that too much 
information was provided on Native harvest while another suggested 
expanding the section to describe geographic patterns of Native 
harvest. Response: Because the focus of the stock assessment was to be 
commercial fisheries incidental take, other human-caused mortality was 
generally described. In the case of human-caused mortality to sea 
otters, this includes Native harvest.
    Other human-caused mortality. Comment: The comment was received 
that the section on human-caused mortality should be expanded to 
include historic information. Response: This section was expanded.

Southern Sea Otter in California

    Annual human-caused mortality. Comment: Sentiment was expressed 
that the Service needs to clarify that southern sea otter mortality 
attributable to drowning in lobster pots is unknown, but may be a 
significant contributor to the lack of population growth at San Nicolas 
Island. It was further stated that this information should be included 
in the ``Fisheries Information'' section of the stock assessment. 
Response: The Service agrees; comments were incorporated into the final 
stock assessment.
    Potential Biological Removal (PBR). Comment: Comment was received 
that the stock assessment should clarify that the NMFS will defer to 
the opinion of the Service regarding PBR for this species, and that the 
option of the Service is that incidental take should remain at zero. 
Response: This comment was noted but not incorporated into the final 
stock assessment. The section on PBR has been expanded and retains the 
clarification that the 1994 amendments to the MMPA do not pertain to 
the southern sea otter. No take is allowed.
    Endangered Species Act (ESA) listing, recovery plan, and 
translocation effort. Comment: Comments were received that the final 
stock assessment should: (1) Note the date and reason for listing this 
stock as threatened under the ESA; (2) indicate that a recovery plan 
has been developed and is being revised; (3) explain that the Service 
has attempted to establish a reserve population at San Nicolas Island, 
California; (4) discuss Public Law 99-625 and the closely associated 
Management Zone to prohibit range expansion and protect fishery 
resources; (5) indicate that a number of otters have entered the 
Management Zone and have died, or may have died, as a consequence of 
efforts to capture and remove them; and (6) discuss that an uncertain 
number of sea otters may have been killed in recent years by small oil 
spills and unusual diseases. Response: These comments were incorporated 
into the final stock assessment.
    Maximum productivity rate. Comment: Comment was received that 
R(max) for the southern sea otter appeared to be closer to 4 
percent or 5 percent rather than the 6 percent rate used in the stock 
assessment and that this should be explained. Response: The 6 percent 
rate continues to be used in the final stock assessment. The Service 
believes that adequate data is presented in the ``Current and Maximum 
Net Productivity Rates'' section to justify use of the 6 percent rate.
    Comment: One commenter believed that the Service should note that 
before 1985, when such fisheries were prohibited, the take of southern 
sea otters was far above the estimates of PBR. Therefore, if 
restrictions on gill nets were lifted, then the southern sea 

[[Page 52011]]
otter would be designated as a ``strategic stock,'' requiring formation 
of a Take Reduction Team to advise on measures that should be taken to 
ensure that incidental take does not exceed the PBR. Response: The 
final stock assessment was modified to incorporate these comments.

Northern Sea Otter in Washington State

    Annual human-caused mortality. Comment: The Service should 
elucidate Indian treaty rights, particularly in relation to MMPA 
recovery objectives. It was further stated that this information should 
be included in the ``Fisheries Information'' section of the stock 
assessment. Response: The ``Annual Human-Caused Mortality'' section of 
the stock assessment was changed to acknowledge the tribal rights 
claim. However, until this issue is legally clarified, the Service is 
unable to provide better information and guidance.
    Comment: A comment was received that the Service should identify 
the number and source(s) of animals translocated to Washington State. 
Response: These comments were incorporated into the final stock 
assessment.
    Maximum Productivity Rate. Comment: One commenter stated that the 
Service should describe and discuss data used to determine that 
R(max) is 12 percent for the Alaska sea otter in Washington State. 
Response: The ``Population Size'' section was modified slightly and now 
describes the type of data and survey techniques used. However, actual 
survey counts were not included in the final stock assessment.
    Sea otter/fishery interaction. Comment: One commenter indicated 
that the Service should include information on sea otter/fishery 
interactions in Washington State. Response: This suggestion was 
incorporated into the final stock assessment.
    Comment: One commenter stated that the Service should indicate the 
present distributions of sea otters and gil-net fisheries in Washington 
State coastal waters. Response: The Service agrees and has incorporated 
the comment into the final stock assessment.

West Indian Manatees

    Annual mortality data. Comment: Comments was received that the 
Service should use the most recent mortality data for the Florida 
manatee. Response: The Service concurs. Summary data through December 
1994, as provided by the Florida Department of Environmental 
Protection, has been incorporated into the final stock assessment.
    Stock definition and range. Comment: One commenter questioned the 
Service's definition of a single stock of Florida manatees and 
suggested that an Atlantic coast stock and a Gulf coast stock would be 
more appropriate. Response: The Service considered the merits of 
delineating two stocks of Florida manatees, but prefers to retain a 
single stock classification, noting that genetic studies published to 
date do not strongly support the definition of clearly distinct stocks. 
Furthermore, intensive studies of far south Florida manatee movements 
are lacking, and it may be premature to conclude that no genetic 
exchange between Atlantic coast and Gulf coast animals. Should new 
information become available, the Service will re-evaluate the stock 
definition as needed. Such re-evaluations will be easily accommodated, 
especially in light of section 117 of the MMPA that requires annual 
review and, if appropriate, revision of stock assessments for strategic 
stocks. West Indian manatees, in light of their endangered status, are 
classified as strategic animals.
    Potential Biological Removal. Comment: Concerns were raised about 
the designation of a PBR level for manatees and the implications for 
Section 7 consultations under ESAct and incidental take policy 
regarding manatees. Response: The Service has already addressed these 
concerns in the narrative of the assessments.

Summary of Final Stock Assessments

    Along with the requirement of section 117(b)(3) of the 1994 
amendments to the MMPA that require publication in the Federal Register 
of a notice of availability of final stock assessments, a summary of 
those final stock assessments must also be published. Appropriately, 
the following table lists summary information for the Service's final 
stock assessments for polar bears, walrus, and northern sea otters in 
Alaska, southern sea otters in California and northern sea otters in 
Washington State; and two West Indian manatee stocks in the 
southeastern United States and Puerto Rico.

    Dated: September 20, 1995.
John G. Rogers, Jr.,
Acting Director, U.S. Fish and Wildlife Service.

              Summary of marine Mammal Stock Assessments for Species of Marine Mammals Under Fish and Wildlife Service Management Authority             
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                                                                                                                     Annual                             
                                                                                                                   estimated        Annual              
        Species               Stock area          SRG        FWS       N(min)     R(max)      F(r)       PBR     average human-    fishing-    Strategic
                                                 region     region                                                   caused         caused       status 
                                                                                                                   mortality      mortality             
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Polar bear-Chukchi/     Chukchi and Bering     AKA                7   \1\ N/AV   \1\ N/AV        1.0   \1\ N/AV  55...........  0............  No.      
 Bering Sea stock.       Seas-Alaska and                                                                                                                
                         Russia.                                                                                                                        
Polar bear-Beaufort     Beaufort Sea-Alaska    AKA                7      1,579       0.06        1.0     \2\ 72  63...........  0............  No.      
 Sea stock.              and Canada.                                                                                                                    
Sea otter-Alaska stock  Alaska...............  AKA                7    100,000        0.2        1.0     10,000  506..........  <1...........  No.      
Pacific walrus........  Alaska and Russia....  AKA                7    188,316       0.08        1.0      7,533  5,895........  16...........  No.      
West Indian manatee-    Southeastern U.S.A...  ATL                4      1,822       0.04        0.1          3  \3\ 49.......  <1...........  Yes.     
 Florida stock.                                                                                                                                         

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West Indian manatee-    Puerto Rico..........  ATL                4         86       0.04        0.1          0  2............  Unknown......  Yes.     
 Antillean stock.                                                                                                                                       
Southern sea otter-     Central California     PAC                1      2,376       0.06        0.1   \4\ N/AP  \5\ Unknown..  \6\ Unknown..  Yes.     
 California stock.       and San Nicolas                                                                                                                
                         Island.                                                                                                                        
Sea otter-Washington    Neah Bay to            PAC                1        360       0.12        0.5         11  \7\ Unknown..  \6\ Unknown..  No.      
 stock.                  Destruction Island,                                                                                                            
                         WA.                                                                                                                            
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\1\ N/AV indicates Not Available.                                                                                                                       
\2\ Adjusted upwards to 72 animals from the calculated PBR of 48 to reflect the approximate 2 male:1 female sex ratio of the harvest. See stock         
  assessment for additional information.                                                                                                                
\3\ Estimated average human-caused mortality for the West Indian manatee--Florida stock from 1984-1992. The estimated average annual human caused       
  mortality from 1974-1992 is 36 animals.                                                                                                               
\4\ N/AP indicates Not Applicable. Although the PBR level for the southern sea otter--California stock was calculated to be 7, their incidental take is 
  not governed under Section 118 of the 1994 amendments to the marine Mammal Protection Act.                                                            
\5\ Unknown. Human caused mortalities of sea otters have been attributed to drowning in gill nets and lobster/crab pots, shootings, boat collisions,    
  disease, and oil spills. However, data are insufficient for estimating annual losses. See stock assessment for additional information.                
\6\ Unknown. Observer coverage is inadequate to estimate annual fishery mortality.                                                                      
\7\ Sea otters in Washington State ares susceptible to the same sources of human-caused mortality as they are in California.                            


[FR Doc. 95-24622 Filed 10-3-95; 8:45 am]
BILLING CODE 4310-55-M