Effects of Large Overwater Structures on Epibenthic Juvenile Salmon Prey Assemblages in Puget Sound, Washington.

摘要

Although large over-water structures alter nearshore habitat in a number of ways, little work has been done to study how docks affect nearshore fauna. In Puget Sound, juvenile chum, pink, and oceantype chinook salmon migrate along the shorelines and feed extensively on shallow water epibenthic invertebrates. As part of an ongoing project on the effects of ferry terminals on juvenile salmon, this study looked at the effects of large overwater structures on juvenile salmon and their prey. The epibenthic assemblage was sampled for juvenile salmon prey with four sampling regimes: monthly-stratified sampling of epibenthic invertebrates at three terminals, one-time eelgrass patch at a single terminal, onetime high-resolution cross-terminal at a single terminal, and one-time terminal structure sampling at two terminals. The response variables tested included taxa richness and densities of (1) total epibenthos, (2) total juvenile salmon prey, (3) common or abundant salmon prey taxa and (4) common or abundant nonsalmon prey taxa.