Threadfin Shad Impacts Phytoplankton and Zooplankton Community Structures in Channel Catfish Ponds

Authors

Bartholomew W. Green, USDA ARSFollow
Peter Perschbacher, University of Arkansas at Pine Bluff
Gerald Ludwig, USDA, Agricultural Research Service
Sara E. Duke, USDA, Agricultural Research Service

Date of this Version

2010

Citation

Green, B., P. Perschbacher, G. Ludwig, and S. E. Duke. 2010. Threadfin Shad Impacts Phytoplankton and Zooplankton Community Structures in Channel Catfish Ponds. Aquaculture Research 41, e524-e536.

Comments

US gov't work

Abstract

Plankton community structure and chlorophyll a concentration were compared in 12 0.1-ha earthen ponds co-stocked with channel catfish (Ictalurus punctatus Rafinesque, 1818) in multiple-batch culture (initial biomass = 5,458 kg ha^-1) and a planktivore, threadfin shad (Dorosoma petenense Güther, 1867; initial biomass = 449 kg ha^-1), during the April-November growing season. We used a completely randomized design in 2 x 2 factorial arrangement to test planktivore level (presence or absence of threadfin shad) and channel catfish feeding frequency (daily or every 3^rd d). Channel catfish were fed a 32% protein feed to apparent satiation on days fed. The presence of threadfin shad affected phytoplankton and zooplankton community structure more than did feeding frequency, and the impact in ponds was more pronounced after 1 July. Numbers of all major groups of zooplankton were lower in ponds with threadfin shad, but were unaffected by feeding frequency. Chlorophyll a concentration before 1 July was higher in ponds with threadfin shad and unaffected by feeding frequency, whereas after 1 July it was higher in ponds without threadfin shad and that were fed daily. Phytoplankton community structure after 1 July was dominated by nuisance algal bloom genera of cyanobacteria in ponds without threadfin shad and by Bacillariophyceae in ponds with threadfin shad.