Skip to Content


Marine Mammal Protection Act; Stock Assessment Report

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble


Fish and Wildlife Service, Interior.


Notice of availability of final revised marine mammal stock assessment report for the northern sea otter stock in Washington State; response to comments.


In accordance with the Marine Mammal Protection Act (MMPA), the Fish and Wildlife Service (Service) has incorporated public comments into a revision of the marine mammal stock assessment report for the northern sea otter (Enhydra lutris kenyoni) stock in Washington State. The 2008 final stock assessment report is now complete and available to the public.


Send requests for printed copies of the final stock assessment report to: Manager, U.S. Fish and Wildlife Service, Western Washington Fish and Wildlife Office, 510 Desmond Drive SE, Suite 102, Lacey, WA 98503; (360) 753-9440. Copies of the final revised stock assessment report are also available on the Internet in Adobe Acrobat format at​westwafwo.

End Preamble Start Supplemental 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 Start Printed Page 60712prepare 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 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.

A draft revised stock assessment report for the northern sea otter stock in Washington State was made available for a 90-day public review and comment period on April 17, 2008 (73 FR 20931). Prior to releasing it for public review and comment, the Service subjected the draft report to internal technical review and to scientific review by the Pacific Regional Scientific Review Group established under the MMPA. Following the close of the comment period, the Service revised the stock assessment and prepared the final 2008 stock assessment report.

We revised the final stock assessment report based on public comments received (see below). The status of the stock remains unchanged from the draft revised SAR that was provided for public comment; however, the PBR level was amended to reflect the results of the 2007 survey conducted by the Washington Department of Fish and Wildlife. We also provided further clarification in the discussion of fisheries information as it relates to reports of incidental take. Most of the public comments received were addressed by adding new text for clarity.

A summary of the final revised stock assessment report is presented in Table 1. The table lists the stock's Nmin, Rmax, Fr, PBR, annual estimated human-caused mortality and serious injury, and status.

Table 1—Summary of Final Revised Stock Assessment Report for the Northern Sea Otter Stock in Washington State

StockNminRmaxFrPBRAnnual estimated average human-caused mortalityStock status
Northern sea otters (Washington State)1,1250.200.111UnknownNon-Strategic

Comments and Responses

The Service received comments from 2 entities on the draft stock assessment report. The issues raised in those comments and our responses are provided below.

Comment 1: The Service should clarify that the next revision on this assessment will be prepared within 3 years or sooner, if the Washington stock expands its range into Oregon or British Columbia, or undergoes any significant change in the status of the stock.

Response: The Service will continue to review available information on an annual basis and revise the stock assessment report at least once every 3 years for the northern sea otter in Washington State, as specified under section 117 of the MMPA. Section 117(c) directs the Service to review a stock assessment if significant new information indicates that the status of the stock has changed, which could occur prior to the end of the next 3 years. If the Service obtains new information that indicates this stock has established a range significantly beyond the current range, or has undergone some other significant change, the Service will review the stock assessment report and revise as appropriate at that time.

Comment 2: The Nmin, PBR, and Figure 2 should be amended to reflect the results of the 2007 survey conducted by the Washington Department of Fish and Wildlife and appropriate references to the unpublished reports, both 2006 and 2007, should be provided.

Response: The Service agrees with this comment and has updated the stock assessment report to reflect the 2007 survey data. The 2007 survey data identifies an Nmin of 1,125 and, therefore, the re-calculated PBR is 11 animals. The citations have also been updated to indicate that information on the 2006 and 2007 unpublished survey data may be obtained by contacting the Washington Department of Fish and Wildlife.

Comment 3: In the discussion under Fisheries Information, clarify the location of Fishery Areas 4 and 4A and when this fishery was last active. In reference to Observer Coverage in these fisheries, listed in Table 1, provide further clarification as to what is meant by “1-11 net days observed.”

Response: The location of Fishery Areas 4 and 4A has been clarified. The information supplied to us by the Makah Tribe and the NMFS regarding the Makah Northern Washington Marine Set-gillnet Fishery was not broken out by Fishery Area; therefore, we can not provide further fishing effort beyond the activity level already included in Table 1 in the stock assessment report. The observer coverage information provided in Table 1 in the stock assessment report is in the format provided by the sources. Further clarification is not available to us for inclusion in the stock assessment report.

Comment 4: Clarify whether the NMFS, who collects data through a self-reporting system on the incidental take of marine mammals in fisheries, has received reports of sea otters taken in treaty and non-treaty fisheries in Washington State or has simply not Start Printed Page 60713provided the reports to the Service. Specify the corresponding time frame.

Response: The Service has updated the stock assessment report to reflect the requested changes. However, the information provided by the NMFS did not include a time frame; therefore, a time frame has not been included in the updated stock assessment report.

Comment 5: Given the apparent lack of voluntary reports of sea otter takes and the unreliability of voluntary reporting schemes in general, remove the word “more” from the sentence on page 5 that states “* * * the information provided by the NMFS is not sufficient to provide a more accurate estimate of annual mortality * * *.” Further, a statement should be made that a useful estimate of fishing mortality will require instituting observer coverage to obtain data on fishery efforts.

Response: We have revised the final stock assessment report to reflect this comment. The fishery observer programs are conducted by the NMFS of the Department of Commerce, and, therefore, institution of observer coverage in fisheries must be directed to them. We have forwarded this suggestion to them (see response to comment 6).

Comment 6: The stock assessment report concludes that available information is not adequate to make a reliable assessment of incidental take levels. Therefore, the Service should consult with NMFS, Tribal authorities, and other relevant groups to arrange for the placement of observers aboard trap and gillnet fishing vessels that may incidentally take sea otters.

Response: The fishery observer programs are under the administration of the NMFS in accordance with section 118 of the MMPA. With the exception of the Puget Sound Region salmon drift gillnet, all commercial fisheries in the State of Washington that have the potential to take sea otters are classified as Category III in NMFS' List of Fisheries. Category III fisheries are not required to accommodate observers. Further, under this program, fishery interactions are self-reporting or, in some cases, identified as excluded, e.g., treaty Tribal fishing. It is the position of the Service that the incidental take of sea otters by treaty Tribal fishing activities must be authorized under the MMPA. Nonetheless, obtaining incidental take information is a challenge. However, the Service will continue to work with the NMFS, Tribal authorities, and others to the extent practicable under these conditions to obtain better data.

Comment 7: Illegal taking of sea otters is being perpetrated by “fish profiteers” and the Service is not taking appropriate action.

Response: The stock assessment report presents all of the human-caused mortality of sea otters that has been made known to the Service.

Reference Not Cited in the Notice of Availability of Draft Revised SAR:

Jameson, R.J. and S. Jeffries. 2008. Results of the 2007 Survey of the Reintroduced Sea Otter Population in Washington State. Unpublished Report. 7pp. Copies may be obtained from the Washington Department of Fish and Wildlife.

Start Authority

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

End Authority Start Signature

Dated: October 2, 2008.

Kenneth Stansell,

Acting Director, Fish and Wildlife Service.

End Signature End Supplemental Information

[FR Doc. E8-24195 Filed 10-10-08; 8:45 am]