Historic Dietary Aspects of Juvenile Pacific Salmon (Oncorhychus spp.), Pacific Herring (Clupea pallasii), and Eulachon (Thaleichthys pacificus) in the Strait of Georgia from 1966 to 1968

The ecosystem approach intended by fisheries management frameworks aims to manage fisheries target species as part of a larger ecosystem, incorporating variables such as climate and community interactions into management decisions. The approach, however, requires a larger breadth of information than traditional fisheries management. The Fraser River plume is a prominent feature in the Strait of Georgia associated with increased zooplankton abundance and, subsequently, juvenile salmon residence. Using an unpublished historical data set collected in the Fraser River plume between 1966 and 1968, we have investigated the diets of juvenile salmonids along with a potential competitor, Pacific Herring, to gauge potential species interactions in the spring and early summer. During this time, salmonids are opportunistic generalists with high individual variation and low between species variation in diets, although certain species, such as Chinook and Sockeye Salmon, show clear differentiation and some species of prey appear particularly important. Herring and eulachon diets are unique when compared to salmon during this time. We hope that these historical data can be compared to recent or future studies and aid ecosystem approaches to salmon management by identifying potential differences in feeding habits or species interactions, particularly in relation to changing environmental conditions.