CHAPTER VII 



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 

 Commission, to develop regulations governing the incidental 

 taking of marine mammals by persons subject to the juris- 

 diction of the United States. It also calls upon the 

 Secretaries, again in consultation with the Commission, to 

 develop effective international arrangements, through the 

 Secretary of State, for the purpose of reducing the inci- 

 dental 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 

 different 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 years, been the 

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

 versy. Of more recent concern has been the incidental taking 

 of Dall's porpoises 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 Conser- 

 vation 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 1986 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 IX of this 

 Report. Interactions between fisheries and other marine 

 mammals are discussed in Chapter VI. 



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 con- 

 tinued to devote substantial attention to the issue in 1986. 

 In mid-October 1986, the U.S. tuna fleet reached the inciden- 



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