JOINT COHO TECHNICAL COMMITTEE

Joint Coho Technical Committee. Northern Panel Area Coho Salmon Status Report. TCCOHO (91)-1. December, 1991.

Coho salmon stocks in the PSC Northern Panel Area contribute to a wide array of fisheries in Canada and Alaska. In the fall of 1988, the Coho Technical Committee was assigned the task of compiling available information on Northern Panel Area coho salmon stocks and fisheries. This report presents the results of a preliminary review of the information in four major areas; (1) fishery catches and trends; (2) fishery management descriptions; (3) stock descriptions and status; and (4) research required to improve coho salmon management in the Northern Panel Area.

Although the total commercial catch of coho salmon by each country in the Northern Panel area has varied widely from year to year, for the most part they have varied together. To the extent that catch is an indicator of abundance, then this similarity in trends may be due to the similar freshwater and/or early marine environmental conditions experienced by coho salmon in the Northern Panel area. Research in southern British Columbia and the Pacific Northwest indicates that temperature and rainfall during freshwater rearing, and coastal upwelling during early ocean life are important factors in determining survival rates to the adult stage.

Since Alaskan statehood, and until approximately 1977, the northern British Columbia commercial catch of coho salmon was slightly higher than the S.E. Alaskan catch. Since 1977, the total S.E. Alaskan commercial catch has been greater. The greater S.E. Alaskan commercial catches may be attributed to several factors. There may have been a higher survival of coho salmon in S.E. Alaska than in northern B.C. There has been a gradual shift by the S.E. Alaska troll fleet to some outside areas thus increasing the number of stocks available for harvest, and the time and area other stocks would be exposed to fishing. Returns from hatchery programs in S.E. Alaska have been greater than those in northern B.C. Finally, there has been more targeting by the S.E. Alaskan troll fleet on coho due to shortened chinook salmon seasons resulting from PST chinook catch ceilings.

Except for the exclusion of purse seines from Icy Straits in SEAK area 4, the pattern of net fishing in Southeast Alaska has remained essentially unchanged since statehood. The troll fishery is responsible for the majority of the increase in the S.E. Alaskan catch. The average troll catch during the 1985 to 1989 period increased by 776,863 (135%) over the average catch during the 1960's. The average purse seine catch during the period 1985 to 1989 increased by only 4,995 (2%) over that of the 1960's while that of the drift and set gillnets' increased by 120,710 (101%) and 39,076 (34%) respectively.

In northern B.C., the total commercial coho catch has not shown an increasing or decreasing trend over time, although the 1960's was a decade of high average catch (1,380,036) relative to the 1950's (1,012,246), 1970's (968,078) and 1980's (925,008). Over this period of time, the troll and seine fleet have increased their proportion of the commercial catch while the gillnet fleet has taken a sharp reduction. Gillnets and seines no longer target on coho salmon in British Columbia and their coho catch is taken entirely as a bi-catch in fisheries directed at sockeye, pink and chum salmon. PST chinook restrictions have also influenced the conduct of troll fisheries for coho in northern B.C. A shorter chinook season coinciding with the coho season, and attempts to minimize periods of chinook non-retention have probably resulted in lower harvest rates on coho despite the increase in fishing effort during July and August.