Diet of Juvenile Quillback Rockfish (Sebastes maliger) from Puget Sound, WA

Rockfish (Sebastes spp.) in Puget Sound, Washington are among the most threatened marine fish stocks in North America. Survival of juvenile rockfishes occupying nearshore nursery habitats is critical in determining stock status. Little is known about the feeding ecology of juvenile rockfishes in Puget Sound. The diets of 161 juvenile quillback rockfish (S. maliger) collected from two nearshore marine algal habitats, Edmonds and West Point, in central Puget Sound, Washington State, were analyzed to investigate their food habits. Genetic analysis was used to confirm quillback rockfish identifications as many rockfish taxa are morphologically indistinguishable at small sizes.  Diet data were used to determine habitat use by the juvenile rockfish based on habitat affinities of the prey.  Samples were grouped by Total Length size ranges; 25-44mm and 45-64mm – Edmonds, and 45-64mm and 65-84mm – West Point. At Edmonds, diet of the smaller size group was primarily pelagic calanoid copepods and substrate associated harpacticoid copepods, and the diet of the larger size group was gammarid amphipods and small Carideans (almost all family: Hippolytidae). Shrimp dominated diets in both West Point size groups. Juvenile quillback rockfish appeared to shift foraging from pelagic to epibenthic/epiphytic habitats between 43 to ~55 mm length.