|Mischke, C - MISS. STATE UNIV.|
|Brashear, S - USDA-SRRC|
Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 13, 2002
Publication Date: March 3, 2003
Citation: Zimba, P.V., Mischke, C.C., Brashear, S. 2003. Pond-age water column trophic relationships in channel catfish ictalurus punctatus production ponds. Journal of the World Aquaculture Society 219:291-301. Interpretive Summary: Management of culture production ponds is critical to maintain high levels of fish production. The relative youth of the catfish industry has resulted in few studies examining the effect of pond age on optimal water quality characteristics within these ponds. This study examined ponds of 1-15 years of age. A clear change in pond function was evident after 3-4 years of use; this change included increased abundance of cyanobacteria, off-flavor, and higher concentrations of nutrients. Draining ponds every 3-4 years should decrease occurrence of off-flavor in these ponds and improve overall water quality.
Technical Abstract: Long-term temporal succession changes in nutrients, phytoplankton and zooplankton have not been previously investigated in aquaculture ponds. This study analyzed relationships of pond age with nutrients, zooplankton and phytoplankton populations, and incidence of off-flavor occurrence. Nutrient levels (iron, silica, total phosphorous, and total nitrogen), phytoplankton community composition, off-flavor compounds, and zooplankton community composition were determined for 10-11 replicate commercial channel catfish Ictalurus punctatus production ponds of ages 1, 2, 3, 4, 9, 10 or 15 years post-construction. Data were analyzed using canonical discriminant function analyses, MANOVA, and multiple regression approaches. Nutrients (N and P) accumulated in ponds during the first 3 years post-construction; however, concentrations of these nutrients leveled off after this time. The continual addition of nutrients (as feed) makes standard chlorophyll:P relationships reported from natural lakes unable to account for variation in aquaculture data. Algal composition became dominated by filamentous cyanobacteria after year 4; zooplankton composition also was dominated by larger copepods and cladocerans in older ponds. Younger ponds had lower incidence and intensity of off-flavor relative to older ponds. If ponds are drained/reworked every 3-4 years, incidence of off-flavor should decline.