Evaluating zooplankton in traditional and split-pond systems for raising golden shiners, Notemigonus crysoleucas

Abstract

We hypothesize for golden shiners, Notemigonus crysoleucas, raised in split-ponds (SPS), that the waste treatment unit (WTU) would be a zooplankton refuge. To examine this hypothesis, a 6-week study was conducted in six traditional earthen ponds (TEP) and six SPS (each 0.04 ha) stocked with adult golden shiners at 450 kg of fish/ha. Fish were fed a commercial feed at 3% body weight daily in three ponds (FED) of each pond type, while in the remaining ponds fish had access to natural foods only (UNF). Zooplankton samples were collected daily for five consecutive days from three locations in each TEP and from three locations each within the fish culture unit (FCU) and WTU of SPS. Net yield and survival were not significantly different among the treatment groups. Survival was severely impacted by depredation from birds and herpetofauna. Fish in SPS-UNF ponds had lower condition factors, relative weight, whole-body fats, and gonadosomatic index compared to the other treatment groups. Zooplankton number/mL were significantly higher in the TEP (both FED and UNF) when compared to other treatment groups. There was not enough evidence that the WTU being devoid of fish may serve as a refuge for larger zooplankton.