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United States Department of Agriculture

Agricultural Research Service

Title: A Synoptic Survey of Musty/muddy Odor Metabolites and Microcystin Toxin Occurrence and Concentration in Southeastern Usa Channel Catfish (Ictalurus Punctatus Ralfinesque) Production Ponds

item Zimba, Paul
item Grimm, Casey

Submitted to: Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 11, 2002
Publication Date: January 1, 2003
Citation: Zimba, P.V., Grimm, C.C. 2003. A synoptic survey of musty/muddy odor metabolites and microcystin toxin occurrence and concentration in southeastern usa channel catfish (ictalurus punctatus ralfinesque) production ponds. Aquaculture.

Interpretive Summary: Pond raised aquaculture species can accumulate odorous compounds that result in fish considered unmarketable. Fish can also uptake toxic compounds produced by cyanobacteria. Knowledge of the spatial distribution of these compounds is limited. This study was designed to identify the concentration of off-flavor compounds (geosmin, 2-methylisoborneol, and beta-cyclocitral) and toxin microcystin in 486 catfish production ponds located in Alabama, Arkansas, Louisiana, and Mississippi. The off-flavor compounds MIB and geosmin were present in ca. 25% of ponds; whereas, the woody off-flavor compound beta-cyclocitral occurred in 96% of the samples. Microcystin was found in 47% of the samples analyzed.

Technical Abstract: A synoptic profile was completed in July-August 2000 to assess the occurrence of off-flavor compounds (beta-cyclocitral, 2-methylisoborneol-MIB, and geosmin) and the cyanobacterial toxin in catfish production ponds. A total of 485 ponds were sampled during a one-week period; sample collections were weighted to reflect state acreage in production. Over 47% of ponds had detectable toxin concentrations; however, less than 10% of ponds exceeded 1 ng/mL microcystin. MIB and/or geosmin off-flavors occurred in 25% of the samples. Beta-cyclocitral was detected in over 98% of ponds, and was strongly correlated with presence of myxoxanthin (r = 0.94) and zeaxanthin (r = 0.82), both indicative of cyanobacterial production of this compound. Off-flavor compounds (geosmin and 2-methylisoborneol) were correlated to a lesser degree with zeaxanthin production (r = 0.78), whereas aphanizyphyl was better correlated to MIB and geosmin (r = 0.89 and 0.56, respectively) again suggesting cyanobacterial production of these compounds.

Last Modified: 4/22/2015
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