Diet and prey selection of naturalized smallmouth bass in an oligotrophic Adirondack lake

Smallmouth bass (Micropterus dolomieu) introduced nearly 50 years ago have established a permanent population in Little Moose Lake, NY. Over 500 small mouth bass were collected by angling in the littoral zone from June to Augu st. Gut contents were compared for differences based on length of bass, dat e of capture, and substrate type where each fish was caught. Crayfish were the most frequent diet item and made up the largest percent composition by number. The average number of crayfish per stomach increased with bass leng th as did the number of fish per stomach. Crayfish, Ephemeroptera, Odonata, and fish made up 77% of the total number of diet items, excluding zooplank ton. A noticeable diet shift from smaller diet items (Ephemeroptera) to lar ger ones (crayfish and fish) occurred when smallmouth bass approached 150 m m. A high amount of diet overlap occurred between bass caught over differen t substrate types and among most size classes. Smallmouth bass in Little Mo ose Lake were opportunistic feeders, using benthic, terrestrial, and pelagi c Littoral zone food resources. The most likely processes by which smallmou th bass affect salmonid and native fishes in Little Moose Lake are competit ion for food resources and predation.