This study develops preliminary estimates of total whaling-induced mortality of northern right whales in the 19th century North Pacificpelagic whale fishery. Best’s (1987) study of American whaling returns resulted in estimates of the total American catch of 14,480 and15,374 northern right whales during the period 1839-1909. The present study offers adjustment factors to estimate total mortality from thesecatch data. Quantitative data from 14 pelagic expeditions for northern right whales in the North Pacific from 1838-1860 and additionalanecdotal information about struck-but-lost animals is reviewed. On 12 voyages, 327 northern right whales were struck with harpoons, butonly 133 landed. Adjusted for the subsequent recovery of struck whales, this implies a ratio of 2.43 whales struck for each whale eventuallysecured and flensed by whaleships. Data from four voyages show that of 148 northern right whales struck with harpoons, 14 sank beforethey could be processed. From a sample of five voyages, 80 northern right whales were landed and 31 carcasses sank without being secured.During the height of pelagic whaling in the North Pacific, approximately 10% of the fleet was non-American, primarily French. Adjustingrecorded catch estimates for struck-but-lost mortality and non-American whaling yields preliminary estimates of total mortality in thisfishery in the range of 26,500-37,000 animals during the period 1839-1909. In the single decade of 1840-49, between 21,000-30,000northern right whales may have been killed in the North Pacific, Sea of Okhotsk and Bering Sea, representing about 80% of the northernright whales killed in this region during the period 1839-1909.
Recent observations of critically endangered North Pacific right whales (Eubalaena japonica) off the west coast of Canada