Management of the Pacific Halibut Fishery

Abstract

The International Pacific Halibut Commission (IPHC) has managed the Canadian and United States halibut fishery since 1923. During the early years of the Commission the abundance of the halibut stocks was declining and there were major changes in fishing techniques. After 1930 the Commission instituted more regulatory control, and catches gradually improved, reaching a maximum in the early 1960s. Some scientists attribute IPHC’s success to its organizational structure; others credit the simplicity of the fishery; still others contend that success was possible because the two nations have similar cultures. A more important factor has been the control of the fishery, i.e. the authority to introduce conservation measures that are supported by adequate enforcement.Since 1960 IPHC has lost control of certain elements in the fishery, and the abundance of halibut has declined markedly. The total catch by the North American longline fleet in 1962 was approximately 45,000 metric tons, while in 1972 it was 25,000 metric tons (round weight). Maximum catch per unit effort (CPUE) was reached before the expansion of domestic (Canada and United States) and foreign trawling. In the late 1950s IPHC had increased the removals to test the estimated maximum sustained yield (MSY) of the stock and expected a decline in CPUE when fishing intensity was increased; however, the rate of decrease was greater and lasted longer than anticipated. Changes in recruitment may have contributed to this decline. By 1965, the incidental catch of halibut by foreign and domestic trawl fisheries had increased substantially, and this accelerated the decrease in abundance. Reductions of the catch limits of the longline fleet failed to arrest the decline. In addition, longline fishermen had improved the effectiveness of their gear by increasing the spacing between hooks; as a result IPHC’s measure of CPUE since 1960 was overestimated. The effects of this gear change are far reaching and basic parameters of the halibut populations must be reassessed. Though the fishery has changed measurably, and IPHC has lost some control through the incidental catch by trawlers, a viable fishery has been maintained through the sacrifice of yield by the North American longline fleet. Productivity of this fishery is in jeopardy because losses to trawl fleets are not controlled, and continue to increase.