Response of biota to aeration rate in low water exchange ponds farming white shrimp, Penaeus vannamei Boone

The response of phytoplankton, zooplankton and benthos to four aeration rates was evaluated in ponds farming white shrimp, Penaeus vannamei Boone, with less than 5% water exchange. Phytoplankton biomass (measured as chlorophyll-a) was higher in ponds with aeration rates of 0 and 6 h day-1 than in those with rates of 24 h day-1. The abundance of zooplankton and benthos (organisms m-2) were higher in ponds with aeration rates of 0 and 6 h day-1, and lower in ponds with rates of 12 and 24 h day-1. The nauplii of different crustaceans, copepods and larval polychaetes were the most abundant organisms of the zooplankton community. Differences in zooplankton composition were observed among treatments. Polychaetes were the most abundant benthic organisms during the culture period. These organisms were more abundant in ponds with lower aeration rates. The guts of shrimp from ponds with aeration rates of 0 and 6 h day-1 had a higher abundance of zooplankton and benthic organisms than those from the other treatments. That abundance decreased over time in all treatments. Shrimp had better growth in ponds with an aeration of 6 h day-1. Survival and yield were similar in ponds with aeration rates of 6, 12 and 24 h day-1, and lower in ponds with rates of 0 h day-1.