Chapter III — Species of Special Concern 



tion in important gray whale breeding areas and 

 feeding grounds. 



In September 1995, the Service published final 

 stock assessments for marine mammal stocks in 

 Alaska, including eastern North Pacific gray whales. 

 For the gray whale stock, the assessment cited 23,109 

 individuals as the best estimate of population size, and 

 four percent per year as the best estimate of maximum 

 net productivity. Based on this and other information, 

 it determined the potential biological removal level to 

 be 434 animals per year. From observer data and 

 fishermen logbook data, the Service concluded that 

 only a few individuals per year were killed or serious- 

 ly injured in gillnets. It also concluded that human- 

 caused mortality and serious injury does not exceed 

 the estimated potential biological removal level and 

 that the stock therefore should not be considered a 

 strategic stock. 



Research and Monitoring 



As noted earlier, the eastern North Pacific stock of 

 gray whales was removed from the List of Endan- 

 gered and Threatened Wildlife in 1994. The Endan- 

 gered Species Act requires that if a species under the 

 Department's jurisdiction is delisted, the Secretary of 

 Commerce must implement a system to monitor the 

 status of the species for at least five years. The 

 National Marine Fisheries Service prepared a draft 

 five-year plan of research and monitoring of the 

 eastern North Pacific gray whale stock, and forwarded 

 the draft to the Commission for review in 1993. 



The plan set forth the following priority-ranked 

 research tasks: (1) estimate abundance from biennial 

 surveys during the southbound migration; (2) estimate 

 calf production by counting calves during the north- 

 bound migration; (3) determine potential biases in 

 methods used to estimate abundance and calf produc- 

 tion; (4) estimate the number of animals killed for 

 subsistence purposes by Russia for its Natives; (5) 

 determine trends in pregnancy rates of animals taken 

 in the subsistence harvest; (6) evaluate the current 

 status of the stock; and (7) determine the degree to 

 which human-caused effects may compromise the 

 viability of the stock and its habitat. 



As discussed in the previous annual report, the 

 Commission provided comments to the Service on 29 

 July 1994 recommending, among other things, that the 

 plan be revised to include identification of human 

 activities that could affect the principal calving and 

 breeding lagoons in Baja California and summer 

 feeding grounds in the Bering and Chukchi Seas; and 

 indicate what will be done to determine the depen- 

 dence of the eastern Pacific gray whale stock on 

 specific feeding and breeding areas. 



At the end of 1995 the final plan had not been 

 completed and it was the Commission's understanding 

 that the plan would be finalized and released in early 

 or mid 1996. Early in 1996, the Commission expects 

 to write to the Service to inquire about the status of 

 the plan. 



Although the plan has not been completed, the 

 Service has undertaken a number of gray whale 

 monitoring studies. Shore-based abundance surveys 

 were done during the southbound migration at Granite 

 Canyon, California in 1992-1993, 1993-1994, and 

 again in 1995-1996. The abundance estimate from the 

 1993-1994 survey is 23,109. These surveys also 

 revealed that proportionally more calves are being 

 seen during the southward migration than in previous 

 studies, some of which date back several decades. 

 This finding indicates that for some individuals 

 calving occurs prior to migration and suggests a trend 

 toward successively later migrations. 



In 1994 and 1995 shore-based surveys were done to 

 estimate the number of northward migrating gray 

 whale calves passing Piedras Blancas, California. 

 Estimates of calf production were 4.3 percent of the 

 population in 1994 and 2.7 percent in 1995. The 

 reasons for the decrease in the estimated calf produc- 

 tion for 1995 is not known. In addition, studies were 

 done to assess and reduce potential biases in the visual 

 abundance surveys. In 1993-1994 and 1994-1995 

 aerial surveys were done to determine the offshore 

 distribution of migrating whales and thermal sensors 

 were used to measure day/night migration rates. The 

 thermal sensor study revealed no differences in pod 

 size or surfacing intervals between day and night. 



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