Juvenile Salmonid and Baitfish Distribution, Abundance and Prey Resources in Selected Areas of Grays Harbor, Washington
Final rept. Mar-Oct 1980
WASHINGTON UNIV SEATTLE FISHERIES RESEARCH INST
Pagination or Media Count:
A comprehensive studies of juvenile salmonids, English sole, and baitfish and their epibenthic and neritic prey communities was conducted in Grays Harbor in order to evaluate the potential effects of dredging proposed for widening and deepening the existing navigation channel. Quantitative stomach analyses of juvenile salmonids and English sole indicated that they fed mainly in the epibenthic and neritic habitats in which they were captured. Fishes occupying shallow sublittoral or lower littoral habitats fed mainly on epibenthic crustaceans--primarily harpacticoid copepods, cumaceans, and gammarid amphipods--while those captured in neritic habitats tended to be larger in size and fed upon more pelagic prey such as larval northern anchovy and drift insects. Potential impacts of the proposed dredging project were considered to be either a direct reduction in the fish populations as a result of dredging operations or an indirect reduction of the carrying capacity by removal of preferred habitat or alteration of migration or residence patterns. Of the indirect effects assessed in this report, only the permanent loss of shallow sublittoral habitat, estimated to involve 1.1 of the total sublittoral habitat in the estuary, may be deleterious particularly to juvenile chinook and chum salmon, and young-of-the-year English sole, which forage and rear almost exclusively in this habitat in Grays Harbor.
- Biological Oceanography