Environmental Factors Affecting Flavor of Channel Catfish from Production Ponds

Abstract

Environmental variables and the flavor of channel catfish (Ictalurus punctatus) were monitored at 3-4-week intervals during 1982 and 1983 in 11 ponds at Browns, Alabama, and during 1983 in five production ponds near Auburn, Alabama. Off-flavor in fish flesh was most severe in late summer when algal and actinomycete activity in ponds was greatest in response to high water temperatures and large daily applications of fish feed. However, some fish from all ponds were not off-flavor. For example, in August 1982, flavor scores for fish from 11 ponds at Browns ranged from 1.6 to 9.5 (a score above 9 indicates no off-flavor). The earthy-musty flavor of geosmin was the most common and intense off-flavor in fish. Regression analyses between environmental variables and flavor scores failed to yield strong or consistent correlations. Blue-green algae and actinomycetes, which are known to produce geosmin and other odorous compounds, were abundant in ponds with off-flavor fish; however, these microorganisms also were abundant in ponds where fish were not off-flavor. Off-flavor was equally common in fish from ponds with acidic muds and low alkalinity waters and from ponds with alkaline muds and high alkalinity waters, but the lowest flavor scores were recorded in the more alkaline environments.