Submitted to: Water
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/20/2011
Publication Date: 9/29/2011
Publication URL: http://handle.nal.usda.gov/10113/55548
Citation: Hurlburt, B.K., Brashear, S.S., Zimba, P.V. 2011. Detection of cyanobacteria in closed water systems in southern Louisiana. Water. 3:79-86. Interpretive Summary: Catfish aquaculture in the United States suffers losses due to off-flavor events. An off-flavor event is the accumulation of specific chemicals, geosmin and 2-methylisoborneol. The off-flavor compounds impart a dirty/musty flavor to the fish and renders them unmarketable. Cyanobacteria (formerly called blue-green algae) are the most common producers of these compounds in aquaculture. Anecdotal observations that the presence of various cyanbacteria changes throughout the year. In this study, those changes were recorded on a commercial catfish farm.
Technical Abstract: Catfish aquaculture in the United States in 2007 produced about 500 million pounds of processed fillet products. An estimated annual loss of 20% result from the accumulation of the off-flavor metabolites geosmin and 2-methylisoborneol (MIB), which render the fish unsaleable. These metabolites are produced by a few cyanobacterial species present in a milieu of algae, bacteria, and zooplankton that grow in catfish farm ponds. It is clear to anyone familiar with aquaculture that the composition of the microbial community in the ponds changes throughout the year. Recently, we reported how different components of weather correlated with accumulation of off-flavor compounds. In the work described here, we examined the seasonality of cyanobacteria and diatoms, using denaturing gradient gel electrophoresis (DGGE) during weekly sampling over approximately a six month period.