Spatial and temporal variability in feeding and condition of age-0 walleyepollock (Theragra chalcogramma) in frontal regions of the Bering Sea

Dietary composition, feeding intensity, and condition index of age-0 walley e pollock (Theragra chalcogramma) were examined for variations related to t ime of day, location, size of predator, and year. Stomach contents of pollo ck collected at a hydrographic Bent near the Pribilof Islands during Septem ber 1994 through 1996 were compared with those collected on either side of the front. Diets were dominated in all regions by small zooplankton, mainly copepods, pteropods, euphausiids, and chaetognaths, but fish and some epib enthic crustaceans were also consumed. Copepods and pteropods dominated the diet in all years and areas by number, but the diet was more mixed by weig ht with chaetognaths, euphausiids, and fish (small pollock) also being impo rtant. No significant diel differences in the gravimetric composition of ma jor prey taxa were noted. Stomach fullness was highly variable by year and habitat and no significant differences were observed. Stomach fullness peak ed at around sunset for fish <50 mm and at night for the larger fish, imply ing that Feeding chronology changed with ontogeny. Pollock condition factor (Fulton's K) varied from 0.45 to 1.20 (mean=0.77; s.d.=0.09). Year was not found to be an important factor relating to condition, although location w ith respect to the front was important with offshore fish having a signific antly higher condition than those fish found inshore of the front.; (C) 200 0 International Council for the Exploration of the Sea.