Characteristics of Effluents from Baitfish Holding Sheds in Central Arkansas

Abstract

This study characterized effluents from commercial baitfish holding sheds in central Arkansas, the source of about half of U.S. farm-raised baitfish. Nutrient and solid concentrations in effluents were relatively dilute compared with other aquaculture effluents because fish are not fed while in vats. Total phosphorus concentrations, however, were relatively high (median of 0.52 mg/L in spring, 0.32 mg/L in fall), but source water contributed from 83% to 96% of the total phosphorus concentration in baitfish holding shed effluents. Concentrations of total phosphorus similar to those found in study source waters have been documented for other waters from the Mississippi River Valley alluvial aquifer. Daily variations in effluent quality generally overshadowed other temporal variation, with the exception of higher total ammonia concentrations in the spring. Higher loading rates are common in vats in the spring owing to increased baitfish sales. Daily flushing resulted in brief spikes in concentrations of total suspended solids, 5-d biochemical oxygen demand, and total phosphorus; the average contribution of flushing events to total daily loading was estimated to be 5–13%. Results suggest that holding shed effluents could be reused, at least for pond culture, as long as potential disease transmission issues are resolved.

Received September 19, 2011; accepted February 14, 2012

ACKNOWLEDGMENTS

We thank cooperating baitfish farmers for allowing us access to their facilities to collect samples. Also thanks are extended to Prasanna Surathkal, Samikshya Aryal, Anup KC, Sathyanand Kumaran, and Jinyan Sun for assistance in data collection and analysis. Funding was provided by the state of Arkansas.