Food habit analysis of sub-legal black bass in Norris Reservoir, Tennessee

Eight hundred and five sub-legal black bass (Largemouth bass (Micropterus salmoides), smallmouth bass (M. dolomieu), and spotted bass (M. punctulatus)) were sampled from the Loyston Sea area of Norris Reservoir, Tennessee, from August 1992 to November 1994 to determine their food habits. Approximately 45% of these fish (N = 358) contained at least one item in the stomach. Food items were analyzed by three methods: frequency of occurrence, numerical method, and gravimetric method. The predominant food items were crayfish (27% by weight), threadfin shad (24% by weight), and sunfish (20% by weight) (bluegill and y-o-y bass) with other items (in lesser amounts) including minnows, logperch, silversides, flathead catfish, crappie, Daphnia spp., and one frog. Crayfish were an important food item for all three species of black bass in every sample period except May 1993 and May-June 1994 (<5% by weight).

Shad were present in the stomachs throughout the sample periods except in November 1994. Even though shad were at their lowest abundance during the spring because of exploitation by predators and winter die-offs, they were most abundant in the diets of black bass during the May 1993 sample period (largemouth 60% by weight, smallmouth 50% by weight, and spotted bass 77% by weight).

Bluegills and YOY bass were utilized by largemouth during all sample periods except for August 1992, with their greatest use occurring during May 1994 (42% by weight). Stomachs of smallmouth contained small bass and bluegills in the winter (29% by weight) and early spring samples (May 1994, 68% by weight). Spotted bass foraged on sunfishes in December 1993 (21 % by weight) and November 1994 (24% by weight). Crappie rarely occurred in the stomachs of any species of black bass and comprised less than 1.0% of weight, number, and occurrence.