MARINE MAMMAL COMMISSION - Annual Report for 1998 



an environmental assessment and finding of no signifi- 

 cant impact on its proposal to take non-lethal mea- 

 sures to prevent sea lion predation on salmonid stocks 

 at Willamette Falls. During 1998 the Service and the 

 Oregon Department of Fish and Wildlife continued a 

 joint monitoring program to document sea lion preda- 

 tion at the site. Installation of a barrier at an area 

 referred to as the "cul-de-sac," previously the site of 

 sea lion predation, appears to have alleviated the 

 problem in that area. Subsequently, sea lions have 

 been observed foraging for salmon in an area of the 

 falls that is difficult to monitor and inaccessible for 

 purposes of capture or harassment. It appears, 

 however, that only one or two sea lions are present in 

 the area at any one time, and three to five individuals 

 are involved in the foraging behavior. Efforts to 

 capture individual animals using a trap similar to one 

 used at the Ballard Locks have not been successful. 



Investigation of Possible Pinniped Impacts on 

 Endangered West Coast Salmonid Stocks 



As noted above, section 120(f) of the Marine 

 Mammal Protection Act directed the Secretary of 

 Commerce to investigate whether California sea lions 

 and Pacific harbor seals are having significant nega- 

 tive impacts on the recovery of salmonid stocks that 

 are either listed or are candidates for listing under the 

 Endangered Species Act. In addition, the Secretary is 

 to determine whether these pinnipeds are having broad 

 or adverse impacts on the coastal ecosystems of 

 Washington, Oregon, and California. A report on the 

 results of the investigation was to be completed by 1 

 October 1995. 



As a first step, the Service constituted a working 

 group to compile and evaluate existing information on 

 the status and trends of California sea lions. Pacific 

 harbor seals, and the seven species of salmonids found 

 in Washington, Oregon, and California. Based on the 

 results of the review, the working group prepared a 

 report setting forth its findings and recommendations. 

 The report and discussions with the Pacific States 

 Marine Fisheries Commission on behalf of the states 

 of Washington, Oregon, and California formed the 

 basis for the Service's draft report to Congress 

 addressing the impacts of sea lions and harbor seals 

 on salmonids and west coast ecosystems. 



A copy of the draft report, along with the working 

 group's report, was forwarded to the Marine Mammal 

 Commission and others for comment on 3 April 1997. 

 Both reports noted that piimiped predation was not a 

 significant cause of the decline of salmonid stocks. 

 However, because of the depressed condition of those 

 stocks and the documented sea lion predation at the 

 Ballard Locks, the working group report concluded 

 that available information clearly demonstrates that the 

 combination of depressed fish stocks and high preda- 

 tor abundance in restricted areas where salmon are 

 concentrated during migrations can result in signifi- 

 cant negative impacts on local salmonid populations. 

 Expanding on this conclusion, the draft report stated 

 that there are a number of places in addition to the 

 Ballard Locks where such conflicts exist. The Service 

 therefore proposed to recommend that the Marine 

 Mammal Protection Act be amended to authorize state 

 and federal officials to kill California sea lions and 

 harbor seals seen eating salmonids from stocks listed 

 as endangered or threatened or from other depressed 

 salmon stocks if non-lethal deterrence methods have 

 been determined to be ineffective or impractical. 



The Commission, in consultation with its Commit- 

 tee of Scientific Advisors, reviewed the draft report 

 and provided comments to the Service on 9 July 1997. 

 The Commission noted that the Service's draft report 

 did not consider all relevant information and did not 

 reflect the ftill range of views regarding the killing of 

 pinnipeds to conserve salmon stocks or to reduce 

 interactions with human activities. In addition, the 

 Commission noted that, although it was reasonable to 

 conclude that pinniped predation could be having a 

 significant effect on some depressed salmon stocks, 

 information provided in the working group report and 

 in the draft report to Congress provided no evidence 

 that such predation is actually affecting the recovery 

 of any depressed salmonid stocks, other than the 

 winter run of steelhead salmon that migrates through 

 the Ballard Locks, where high predation appears to be 

 due to a combination of specific factors including fish 

 passage through a restricted area. 



The Commission ftirther noted that, although both 

 reports indicated that the declines in west coast 

 salmonid stocks were caused by factors other than 

 pinniped predation {e.g., habitat degradation and 

 overfishing), they did not identify what has been or is 



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