Preliminary Evaluation of Gulf Sturgeon Production and Sustainability of a Zero‐Discharge Pond Water Recirculating Tank System

Abstract

AbstractGiven increasing interest in zero‐discharge aquaculture systems, we conducted a preliminary 17‐month production study of Gulf sturgeon Acipenser oxyrinchus desotoi in a recirculating pond water (RPW) system and a traditional flow‐through well water (FTW) system. Both systems had three 6.1‐m‐diameter tanks stocked with 400 fish (7 g/fish). In the RPW system, water was pumped from a baffled pond containing aquatic macrophytes into the culture tanks and was then gravity discharged back to the pond. Production and feed conversion ratio were better in the FTW system (778 kg/tank and 1.8) than in the RPW system (494 kg/tank and 2.0). Survival was not significantly different between systems (>93%). The RPW tanks had more extreme fluctuations in temperature (7–34°C) than did FTW tanks (19–23°C). The baffled pond seemed beneficial in increasing dissolved oxygen and decreasing ammonia concentrations relative to the RPW tank water. In addition, the RPW system had the advantage of zero discharge. For the FTW system, total loading was 251.4 kg of nitrogen and 19.8 kg of phosphorus; during the same period, 1,683.4 kg of total suspended solids were released. Although the RPW system had benefits, its low production relative to that of the FTW system makes economic feasibility unlikely in commercial sturgeon culture.