Feed the Future Innovation Lab for Collaborative Research on Aquaculture & Fisheries

Pond fertilization studies usually are restricted by availability of ponds forcing researchers to limit treatments to maintain adequate replicates for statistical analysis. Data from a wide range of fertilizer rates applied over a single season in unreplicated ponds were treated using regression analysis to establish the optimum phosphorus application rate for bluegill (Lepomis macrochirus) ponds. The response to phosphorus fertilization conformed to a saturation model (R² = 0.92). Bluegill production increased with greater fertilization rate up to 3 kg P₂O₅ ha^-1,but production was similar (501 - 558 kg ha^-1) at rates of 3 - 7 kg P₂O₅ ha^-1. The observation that 3 kg P₂O₅ ha^-1 per application was adequate phosphorus fertilization for bluegill ponds with sufficient nitrogen agrees closely with the usual recommendation of 4 kg P₂O₅ ha^-1 per application. Results of this re- search also revealed that nutrient assessment in bluegill ponds can be based on total nitrogen and to- tal phosphorus analyses, and Secchi disk visibility may be used as an index of plankton abundance.

NOP 05-A03 (English)(Spanish)