Food and Habitat Use by Different Sizes of Largemouth Bass (Micropterus salmoides) in Alamo Lake, Arizona

ABSTRACT

Each of three size groups of largemouth bass (Micropterus salmoides) differed in foraging behavior and habitat use in an Arizona reservoir. Small bass (< 25 cm TL) were found only in littoral areas and probably required cover to avoid predation. Most intermediate-sized bass (25–38 cm TL) were too large to be predated and were found in aggregations feeding on threadfin shad (Dorosoma petenense) in open limnetic waters. Large bass (> 38 cm TL) were generally found as solitary individuals near submerged structures suitable for ambush feeding. The allometric growth of these fish may have rendered them too bulky to effectively forage in the limnetic zone. Differences in habitat use and foraging behavior for different sizes of largemouth bass in the reservoir appear to be the result of the interaction of the behavioral flexibility of the species, site-specific resources and ecomorphological constraints.