CCGS W.E. Ricker Gulf of Alaska Salmon Survey, October 9 to November 5, 2001

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Abstract

The Highseas Salmon program of Fisheries and Oceans Canada conducted a survey of Pacific salmon in the Gulf of Alaska from October 9 to November 5, 2001. The objectives of the surveys were to (1) evaluate the distribution and ecology of juvenile Pacific salmon (Oncorhynchus spp.) during their first year in the ocean, (2) describe the ambient oceanographic conditions, and (3) quantify the biomass of zooplankton, an important prey for Pacific salmon at sea. Fish, oceanographic, and zooplankton sampling was conducted at stations spanning the area from the west coast of Vancouver Island (48.6°N) to Icy Strait in Southeast Alaska (58.3°N).

A total of 3411 Pacific salmon were caught on the survey. Of these, 2857 were juvenile pink (O. gorbuscha), chum (O. keta), coho salmon (O. kisutch), and sockeye (O. nerka) salmon in their first fall in the ocean and 475 were chinook salmon (O. tshawytscha) under 350 mm in fork length.

Juvenile pink, chum, sockeye, coho, and chinook under 350mm in fork length were caught on the continental shelf within the 1000 m isobath along the coastal length of the survey from the west coast of Vancouver Island to Baranof Island in Southeast Alaska. They were also caught in Queen Charlotte Sound, Hecate Strait, Dixon Entrance, and within the inside waters of Southeast Alaska.

Juvenile chinook from 100 to 199 mm in fork length were uniquely distributed inside the inlets on the west coast of Vancouver Island, and up Rivers Inlet and Burke Channel on the central coast. All were most likely age 0.0 ocean-type chinook based on the information from CWT recoveries made on this survey.

Juvenile pink, sockeye, and coho were significantly larger in size in the north than in the south. Juvenile chum did not vary in size among regions. It was not possible to make a regional comparison of sizes of juvenile chinook for specific ocean age classes due to the considerable overlap among size modes that represent multiple age groups.