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Article Excerpt
Introduction
Bycatch of Pacific halibut, Hippoglossus stenolepis, in nontarget fisheries has been a major resource removal since the 1960's (Williams et al., 1989). Although targeted by directed commercial setline and recreational fisheries, bycatches of halibut occur in many other fisheries involving various gears. The magnitude of bycatch mortality relative to removals from directed fisheries has caused bycatch to be the subject of much research and management control. The International Pacific Halibut Commission (IPHC), the agency charged through a treaty between Canada and the United States with management of the halibut resource, lacks authority and jurisdiction over nondirected fishing, including bycatch. Thus, management of halibut bycatch falls under the purview of the national governments.
Until relatively recently, direct controls over halibut bycatch had been achieved through bilateral agreements enacted by the United States and Canada with other nations. The agreements provided general stipulations for foreign fishing: observers, seasons, closed areas, and limits on the amount of halibut taken as bycatch by each country. International fora, such as the International North Pacific Fisheries Commission (INPFC), served mainly as a venue for discussion and data sharing. Implementation of extended fisheries jurisdiction in the late 1970's passed the development of bycatch controls to agencies of the Canadian and U.S. governments
In this article, we review bycatch of Pacific halibut by nontarget fisheries, the actions that led to the initial international control and resulting measures, the development of bycatch controls by the United States and Canada for their respective fisheries, and the role of the IPHC in discussions between Canada and the United States. We also evaluate approaches and methods to bycatch control and discuss potential future developments.
Bycatch History
Bottom trawl nets were introduced on the Pacific coast of North America in the mid 1910's (Williams et al., 1989). The IPHC prohibited set-nets for halibut in 1938 and the use of any nets in 1944, primarily due to concerns about the harvest of halibut below optimum harvesting size (Hoag, 1971; Skud, 1977). This gear restriction resulted in the retention of trawl caught halibut being prohibited, and the mandatory discarding, with minimal additional injury, of all halibut.
Growth in halibut bycatch followed development of groundfish (1) fisheries, which began in the early 1960's. Up through the 1950's, trawling by U.S. and Canadian vessels for groundfish in the North Pacific was relatively limited. Fishing by vessels from foreign nations, which began in the early 1960's, was more fully developed. Halibut bycatch mortality was relatively small until the 1960's, when it increased rapidly due to distant-water trawl fisheries by Japan, Korea, the U.S.S.R., Poland, and other nations. Total bycatch mortality is estimated to have peaked in 1965 at about 12,800 metric tons (t) (Fig. 1). Bycatch mortality declined during the late 1960's as some of the first bycatch restrictions (e.g. observers and catch accounting) were put into place by the United States, but increased to about 11,900 t in the early 1970's when new areas and species (e.g. walleye pollock) were exploited. During the late 1970's and early 1980's, halibut bycatch dropped to roughly 7,100 t, as foreign fishing off Alaska came under increasing control. By 1985, bycatch mortality had declined to 4,600 t, the lowest level since the IPHC began its monitoring nearly 25 years earlier. Bycatch mortality then increased through the late 1980's, due to the growth of the U.S. groundfish fishery off Alaska and the lack of restrictions on that developing fishery. Bycatch mortality peaked at 12,240 t in 1992 but it declined to 7,417 t in 2003. The decline can be attributed to management regulations that encouraged more efficient fishing practices and the introduction of individual quota management programs for the sablefish, Anoplopoma fimbria, longline fishery in Alaska and the groundfish bottom trawl fishery in British Columbia.
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International Prohibition
During the late 1960's and early 1970's, regulation of foreign fishing fleets in U.S. waters resulted from bilateral agreements between the United States and the national government of the foreign fleet (e.g. Japan, U.S.S.R., etc.). The agreements identified specific areas and time periods when the foreign fishery was not allowed to operate. This often resulted in...
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