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CHAPTER IV 



MARINE MAMMAL/FISHERY INTERACTIONS 



Interactions between marine mammals and fishermen have 

 sometimes presented difficult problems for those concerned 

 with protecting and conserving marine mammal populations 

 while making wise use of available fish resources. One of 

 the most widely known examples of this problem — the 

 interactions between the yellowfin tuna purse seine fishery 

 and porpoises in the eastern tropical Pacific Ocean — was 

 among the factors that led Congress to pass the Marine 

 Mammal Protection Act of 1972. While substantial progress 

 has been made in recent years to reduce porpoise mortality 

 incidental to this tuna fishery, other serious problems have 

 emerged. As discussed in detail in past Annual Reports, the 

 Marine Mammal Commission has devoted considerable attention 

 and funding to efforts to resolve marine mammal/fishery 

 conflicts. This Chapter provides a brief summary of earlier 

 Commission efforts in the area as well as a description of 

 its activities during Calendar Year 1983. 



Background 



Interactions between marine mammals and fisheries can 

 take various forms — sometimes to the detriment of the 

 marine mammal population involved and other times with more 

 impact on the involved fishery. In the former cases, marine 

 mammals can be killed, injured, or harassed, either inadvertently 

 or deliberately, during fishery operations. In the latter 

 cases, marine mammals may take or damage fish on lines or in 

 traps and nets; they may also damage fishing gear during 

 these encounters or when they accidentally become entangled. 

 In some areas, they compete with fishermen for the same fish 

 and shellfish resources. 



Prior to enactment of the Marine Mammal Protection Act, 

 regulated and unregulated hunting, bounty programs, and 

 various forms of harassment were employed in a number of 

 areas in an effort to eliminate or reduce marine mammal-caused 



