Temporal Variability in the Food Habits of Arrowtooth Flounder (Atheresthes stomias) in the Western Gulf of Alaska

Abstract

Within- and among-year variations in the diet and feeding activity of arrowtooth flounder (Atheresthes stomias) were examined in order to expand the existing knowledge of their food habits to include temporal variability in the western Gulf of Alaska. Stomach samples were collected during bottom trawl surveys conducted near Kodiak Island, Alaska, in May and August 2002-2004. In 2002 and 2003, walleye pollock (Theragra chalcogramma) were the dominant prey for arrowtooth flounder (≥ 40 cm total length (TL)), whereas in 2004 the importance of walleye pollock declined significantly. In 2004, the importance of euphausiids and Pacific sand lance (Ammodytes hexapterus) in the arrowtooth flounder diet increased significantly. Several within-year dietary trends were noted during 2004. Most notably, the importance of euphausiids in the arrowtooth flounder diet decreased significantly from May to August, whereas the importance of capelin (Mallotus villosus) increased significantly. Ontogenetic dietary trends were found to vary both temporally and spatially and temporal changes in feeding activity were more pronounced in the smaller arrowtooth flounder (20-39 cm TL). The dietary trends generally reflected differences in prey availability or abundance and highlighted the adaptable feeding behavior of this key predator.

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