Disinfection, microbial community establishment and shrimp production in aprototype biosecure pond

Plankton community establishment and shrimp production in a prototype biose cure pond were compared to three control ponds. The biosecure pond was encl osed and intake water was disinfected, while control ponds were neither enc losed nor disinfected. All ponds were managed with no water exchange and st ocked with 100 postlarvae/m(2), Litopenaeus vannamei. Residual oxidant conc entrations in the biosecure pond dropped rapidly after cessation of chlorin ated water addition. This was followed by a sharp increase in water column bacterial abundance, after which the pond was fertilized and inoculated wit h cultured Chaetocerous gracilis. After crash of the initial C. gracilis bl oom in the biosecure pond, this species was not observed again. Following i nitial large fluctuations in biosecure pond bacterial abundance, phytoplank ton biomass, oxygen consumption and nitrification rates, these parameters a ppeared to stabilize at levels similar to the control ponds. Early season c ompositional differences in phytoplankton, zooplankton, and bacterial commu nities were observed. No differences were seen in late-season phytoplankton and bacteria; however, zooplankton biomass tended to be lower in the biose cure pond than in the control ponds throughout the season. Shrimp productio n in all ponds was greater than 9,000 kg/ha. Production in the single biose cure pond was not a significant outlier compared to production in the tripl icate control ponds.