Food of the Channel Catfish (Ictalurus punctatus) in a Southern Great Plains Reservoir

Abstract

Stomach contents were examined of 196 channel catfish collected from October 1967 through August 1969.Insects, fish and detritus were most frequently found in the stomachs. Channel catfish smaller than 300 mm (total length) fed primarily on invertebrates. Larger fish were piscivorous. INTRODUCTION In the study of the dynamics of fish populations, the assignment of fish species to a feeding category is desirable to present the relationships between predator and prey species (Swingle, 1954; Swingle and Swingle, 1967). This is particularly true when using Swingle (1950) ratios. Numerous food studies of channel catfish (Ictalurus punctatus) indicate that this species is basically omnivorous (Bailey and Harrison, 1948; Clemens, 1954; Russell, 1965; Stevens, 1959). The analysis of the food of channel catfish collected in a turbid southern Great Plains reservoir is presented in this paper. DESCRIPTION OF THE STUDY AREA Lake Carl Blackwell is located 9 miles NW of Stillwater, Okla. Construction of the earth and rockfill dam was completed in 1937, and the lake reached spillway level in 1945 with an approximate capacity of 80 million m3 (65,000 acre-ft, 3700 acres maximum surface area) (Norton, 1968). The maximum depth is 10 m, but most of the lake is less than 6 m. The drainage area is ap-proximately 14 times the size of the reservoir surface area at spillway elevation. The reservoir at spillway level has a shoreline of about 100 miles. The relatively shallow water and low surrounding landscape permits the prevailing winds to keep the lake circulating almost continuously. This circulation keeps the water turbid and causes nearly uniform physical and chemical conditions from top to bottom in most seasons. METHODS Stomachs from 196 fish were examined, and 128 of these contained food (Table 1). These fish were caught between October 1967 and August 1969 primarily by gill netting, although some were captured in wire and barrel traps (Jearld, 1970). Total length was measured. Stomachs were removed and preserved in a 10%o formalin solution. Volumetric determinations were made in graduated cylinders 1 Present address: Biological Laboratory, U.S. National Marine Fisheries Service, Woods Hole, Mass. 2 Cooperators are: The Oklahoma Dept. of Wildlife Conservation, the Oklahoma State University Research Foundation, and the U.S. Bureau of Sport Fisheries and Wildlife.