Abstract

The Highseas Salmon program of Fisheries and Oceans Canada chartered the F.V. Ocean Selector to conduct a survey of Pacific salmon in the Gulf of Alaska from June 16-28, 2002. The objectives of the survey 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. Oceanographic, fish and zooplankton sampling was conducted at stations spanning the area from the west coast of Vancouver Island (48.4°N) to Dixon Entrance (54.2°N).

A total of 1054 Pacific salmon were caught on the survey. Of these, 632 were juvenile pink (O. gorbuscha), chum (O. keta), coho salmon (O. kisutch), and sockeye (O. nerka) salmon in their first summer in the ocean and 65 were chinook salmon (O. tshawytscha) under 350mm in fork length.

Juvenile pink (age 0.0), chum (age 0.0), and sockeye (age X.0) were caught in relatively high numbers at only a few stations on the survey: 391 juvenile pink and 40 juvenile chum were caught on one tow in Estevan Sound on the central coast of British Columbia, and 185 juvenile sockeye were caught on one tow in Queen Charlotte Sound. Juvenile chinook under 350 mm in fork length were caught within the range of 1-20 fish per tow on the shelf off southern Vancouver Island and Juan du Fuca Strait, and within the range of 1-3 fish per tow in Hecate Strait, the inside passageways of central British Columbia, and in Dixon Entrance. Just 5 juvenile coho (age X.0) were caught.

Juvenile pink ,chum, and sockeye on this survey averaged 103, 107, and 128 mm in fork length, respectively. The five juvenile coho ranged from 154 to 244 mm.