CHAPTER IV 



MARINE MAMMAL-FISHERIES INTERACTIONS 



Interaction between marine mammals and sport and 

 commercial fisheries is not a new problem, but is one that 

 appears in some cases to be intensifying. Such interactions 

 can take various forms -- sometimes to the detriment of the 

 marine mammal population involved and other times with more 

 apparent impact on the involved fishery. In the former 

 cases, marine mammals can be killed, injured, or harassed, 

 either inadvertently or deliberately, during fishing operations, 

 The best known and most controversial example of this involves 

 the yellowfin tuna purse seine fishery in the eastern tropical 

 Pacific Ocean, discussed in Chapter V. 



In other instances, marine mammals take or damage fish 

 caught on lines or in traps and nets; they also may 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 or 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 gear damage, fish damage, and fish loss. With the 

 implementation of the Act, there was a moratorium on such 

 taking and, as a result, over the past ten years, animals in 

 some areas apparently have become more niamerous and/or 

 bolder in their interactions with fishermen and fishing 

 gear. 



Columbia River Project 



A 1977 workshop sponsored by the Commission confirmed 

 that there was a potentially acute problem in the Pacific 

 Northwest involving seals, sea lions, and the salmon gill 

 net fisheries in the Copper River Delta area of Alaska and 

 the Columbia River in Washington and Oregon. As a result of 

 workshop recommendations, the Commission provided funds to 



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