Submitted to: Water Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/21/2005
Publication Date: 8/1/2005
Citation: Schrader, K., Dennis, M.E. 2005. Cyanobacteria and earthy/musty compounds found in commercial catfish (ictalurus punctatus) ponds in the mississippi delta and mississippi-alabama blackland prairie. Water Research. 39(13):2807-2814.
Interpretive Summary: Certain types of blue-green algae produce off-flavor compounds that can taint the flesh of channel catfish and prevent catfish farmers from marketing them. Previously, most studies have focused on the types of off-flavor compounds and blue-green algae that are a problem in west Mississippi aquaculture catfish ponds, the largest catfish-producing region in the United States. We identified the frequency of earthy and musty off-flavor compounds and the most common types of blue-green algae in east Mississippi and west Alabama commercial catfish ponds, the second largest catfish-producing region. The most common type of musty-compound producing blue-green alga in west Mississippi was also found to be common in east Mississippi and west Alabama catfish ponds.
Technical Abstract: The compounds responsible for earthy and musty "off-flavors" in farm-raised channel catfish (Ictalurus punctatus) in the southeastern United States are geosmin and 2-methylisoborneol (MIB), respectively. These compounds are produced by certain species of cyanobacteria (blue-green algae) that grow in the aquaculture ponds. Previous research has focused on the species of cyanobacteria found in catfish ponds in west Mississippi (the leading region of catfish production in the USA) while the species responsible for earthy/musty off-flavors in catfish produced in the Mississippi-Alabama blackland prairie (MABP) region (second greatest region of catfish production) have not been described. In this study, we examined water samples from commercial catfish ponds in both regions to contrast the different types of cyanobacteria and assess the prevalence of geosmin and MIB. Filamentous cyanobacteria were more common in west Mississippi compared to the MABP region. the MIB producing cyanobacterium Oscillatoria perornata was present in catfish ponds in both geographic locations. Geosmin was more prevalent in catfish ponds in the MABP region than in west Mississippi.