Chapter III — Marine Mammal-Fisheries Interactions 



mortality of dolphins in the eastern tropical Pacific 

 tuna fishery and to develop plans for such efforts 

 during the subsequent year. The Service is also 

 required to submit a comprehensive report to Con- 

 gress by 1 April 1992 setting forth the results of the 

 efforts to reduce dolphin mortality and recommenda- 

 tions for actions that should be taken to reduce 

 incidental mortality further. 



The Service held the second annual review of its 

 tuna program on 21-22 January 1991. To meet the 1 

 April 1992 deadline for submitting its report to 

 Congress, the Service convened the third, and last, of 

 the annual reviews on 13-14 November 1991. In 

 addition to representatives of conservation groups, 

 U.S. tuna fishermen, U.S. tuna canners, the Marine 

 Mammal Commission, and other Federal agencies, 

 participants included the Inter-American Tropical 

 Tuna Commission and representatives of several tuna 

 fishing nations. Data and trends for the 1990 and 

 1991 fishing seasons were presented at the meetings. 

 Research underway to develop tuna fishing methods 

 that do not involve setting on dolphins was also 

 discussed. 



In conjunction with the November meeting. Com- 

 mission representatives held a one-day meeting with 

 the staff of the National Marine Fisheries Service to 

 review the scientific and other aspects of the Service's 

 tuna-porpoise program. Based on information pre- 

 sented at the reviews, at the end of 1991, the Com- 

 mission was preparing a letter to the Service recom- 

 mending ways the program might be improved. 



Status of Dolphin Stocks 



As noted above, the incidental take permit issued 

 to the American Tunaboat Association in 1980 was 

 legislatively extended, and quotas for eastern spinner 

 and coastal spotted dolphins were added, during the 

 1984 reauthorization of the Marine Mammal Protec- 

 tion Act. The 1984 amendments also directed the 

 Secretary of Commerce to undertake a scientific 

 research program to monitor indices of abundance and 

 trends of dolphin stocks taken incidental to the eastern 

 tropical Pacific tuna fishery. If, based upon data 

 collected under the monitoring program and other 

 information, the Secretary determines that the fishery 

 is having a significant adverse effect on any dolphin 

 stock, the Secretary is required to modify the inciden- 



tal take quotas and/or gear requirements of the Ameri- 

 can Tunaboat Association's permit to the extent 

 necessary to protect the affected stock. 



The Service initiated its monitoring program in 

 1986 and has completed five of the six planned survey 

 cruises. In light of the decreased participation of the 

 U.S. fleet in the fishery beginning in 1990 and the 

 corresponding reduction in dolphin mortality, survey 

 cruises were not conducted in 1991. The monitoring 

 program was designed to detect changes in the abun- 

 dance of northern offshore spotted dolphins (on the 

 order of 6 to 10 percent per year), the stock most 

 frequently taken in the fishery. No significant trends 

 in the abundance of northern offshore spotted, eastern 

 spinner, or other dolphin stocks' were detected from 

 data collected during the five-year monitoring pro- 

 gram. However, for such trends to be deteaed over 

 the five-year survey period, stock sizes would have 

 had to increase or decrease by roughly 40 to 50 

 percent. Analyses based on data collected by observ- 

 ers onboard tuna fishing vessels also indicate no 

 significant trend, suggesting that most dolphin stocks 

 in the eastern tropical Pacific remained stable during 

 the last half of the 1980s. 



The National Marine Fisheries Service convened a 

 workshop in November 1991 to assess the status of 

 dolphin stocks in the eastern tropical Pacific. Repre- 

 sentatives of the Marine Mammal Commission, the 

 Inter-American Tropical Tuna Commission, and the 

 U.S. tuna industry participated. The findings of the 

 workshop will be presented in a report to Congress 

 early in 1991 prior to hearings on reauthorization of 

 the Marine Mammal Protection Act. 



When the monitoring program requirement was 

 enacted in 1984, Congress noted the shortcomings of 

 the system then in place to regulate incidental taking 

 (i.e., determining the status of stocks by comparing 

 estimates of current and historic population abun- 

 dance). Congress intended the new program to be the 

 "primary... source of information for monitoring and 

 assessment of the health and status of affected por- 

 poise stocks." Contrary to Congressional expecta- 

 tions, however, the monitoring program has not 

 proven to be an effective means for determining if 

 marine mammal stocks are being adversely affected by 

 the tuna fishery. In this regard, a draft paper pre- 



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