Distribution and abundance of eight centrarchid fishes were studied on Delta National Wildlife Refuge from August, 1963 through January, 1965. Gear used to collect the fish included rotenone, gill nets, trammel nets, bag seine, minnow seine and electric shocker. Standing crop samples were conducted using rotenone and block-off nets. Salinity was a major factor which limited distribution of centrarchids on the refuge. Pond depth and turbidity were also factors affecting distribution and abundance. Oxygen, carbon dioxide, pH and alkalinity were found to be within suitable levels for fishes during sampling periods. Spotted sunfish had the most diversified distribution of any centrarchid. Largemouth bass preferred the clearer, deeper waters. Warmouth occurred in more turbid waters than other centrarchids. Centrarchids averaged 32.79 per cent of the total standing crop of fishes in area 1, 23.54 per cent in area 2 and 4.44 per cent in area 3. Centrarchidae represented the second largest family in number of species and first in poundage of fishes occurring on the study area. Redear sunfish, warmouth, spotted sunfish, black crappie and largemouth bass were the most abundant centrarchids in descending order.
