CHAPTER VIII 



INCIDENTAL TAKE OF MARINE MAMMALS IN THE COURSE 

 OF COMMERCIAL FISHING OPERATIONS 



The Marine Mammal Protection Act directs the Secretaries 

 of Commerce and the Interior, in consultation with the Commis- 

 sion, to develop regulations governing the incidental taking 

 of marine mammals by persons subject to the jurisdiction of the 

 United States. It also calls upon the Secretaries, again in 

 consultation with the Commission, to develop effective inter- 

 national arrangements, through the Secretary of State, for 

 the purpose of reducing the incidental taking of marine mammals 

 to insignificant levels approaching a zero mortality and 

 serious injury rate. 



Although the incidental taking of marine mammals occurs 

 in the course of several fisheries and involves several dif- 

 ferent species of marine mammals, the "tuna-porpoise" issue 

 involving the incidental mortality and serious injury of 

 porpoises entrapped in purse seine nets used by commercial 

 yellowfin tuna fishermen has, over the past decade, been the 

 subject of the most intense concern, attention, and contro- 

 versy. More recently, there has been concern over the inci- 

 dental taking of Dall's porpoises and other marine mammals in 

 the course of the Japanese salmon gill net fishery in the 

 North Pacific Ocean, a portion of which occurs within the 

 United States' 200-mile Fishery Conservation Zone, and the 

 incidental take of southern sea otters and other marine mammals 

 in gill and trammel nets in California coastal waters. The 

 Commission's activities during 1987 related to the tuna-porpoise 

 and Dall's porpoise issues are discussed below. A discussion 

 on the incidental take of southern sea otters is included in 

 Chapter II of this Report. Interactions between fisheries 

 and other marine mammals are discussed in Chapter VII. 



The Tuna-Porpoise Issue 



Discussions of the Commission's past activities and a 

 historical summary of the efforts to resolve this problem are 

 presented in the Commission's previous Annual Reports. As 

 discussed below, the Commission, the National Marine Fisheries 

 Service, the U.S. tuna industry, and others continued to 

 devote substantial attention to the issue in 1987. In 1986, 

 the U.S. tuna fleet reached the incidental kill quota of 

 20,500 porpoises in mid-October. As a result, the U.S. tuna 

 purse seine fleet was prohibited from fishing for tuna by 

 setting on marine mammals for the remainder of the year. The 

 level of marine mammal mortality observed in 1987 was con- 



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