Feeding ecology of the Bay Goby (Pisces: Gobiidae). Effects of behavioral, ontogenetic, and temporal variation on diet

Abstract

The ontogenetic, diel, seasonal, and yearly variations in gut fullness, diet, and prey diversity for a California estuarine gobiid ( Lepidogobius lepidus Girard) were examined. Also the feeding behavior of this species was described. Small (<50 mm, SL) and large (⩾ 50 mm, SL) gobies consumed similar prey types in different proportions. Major prey items were polychaetes, harpacticoid copepods, gammarid amphipods, molluscs, and other crustaceans. Diets of large and small gobies were not significantly correlated, and larger fish had a more diverse diet. Small fish fed at all times while larger gobies fed primarily at night. Changes in diet may be related to differential prey preferences, feeding chronologies, and increases in fish size. Both large and small gobies displayed seasonal differences in diet and prey diversity. Year-to-year changes in diet also were noted for both size classes. The bay goby uses different feeding behaviors to capture sedentary and motile prey and appears to forage opportunistically. This behavior is probably advantageous in an environment which fluctuates drastically.