Off-Flavor in Channel Catfish from Commercial Ponds

Channel catfish Ictalurus punctatus from 13 ponds with low feeding rates (<40 kg/hectare per day) and 10 ponds with high feeding rates (>50 kg/hectare per day) in west-central Alabama had discernable off-flavor, as determined by sensory evaluation. However, off-flavor became more intense (causing lower sensory scores) as maximum daily feeding rate increased (r = −0.66; P < 0.01). Six ponds with low feeding rates were in pastures for intensive dairy farming, and considerable manure reached these ponds. When these ponds were omitted, the correlation increased (r = −0.75; P < 0.01). Although correlations between chlorophyll α or chemical oxygen demand (COD) concentrations and off-flavor scores were not significant (P > 0.05), ponds with the lowest concentrations of chlorophyll α and COD had the best tasting fish. The blue-green alga Lyngbya sp. was abundant in several ponds where fish had extreme off-flavor.