CHEMICAL ETIOLOGIES OF OFF-FLAVOR IN CHANNEL CATFISH AQUACULTURE

Thirteen ponds used for commercial culture of channel catfish were analyzed bimonthly during the summer and episodes of off-flavor occurred in nine of these ponds. Several compounds were isolated from the water and catfish that correlated with the onset and severity of off-flavor. The compounds most frequently isolated from water, producing off-flavored fish, were beta-cyclocitral and 2-methylisoborneol (MIB). A dehydration product of MIB, 2-methyl-2-bornene, was found in several fish samples and two water samples. Geosmin and 2-methylenebornane were rarely isolated. beta-cyclocitral was rarely isolated from the fish although high concentrations were isolated from water samples collected from ponds containing off-flavored fish. These compounds were not found in ponds producing on-flavored catfish.