( Influence of season and fertilizer applied on the organic production in ponds.II. Secondary and fish Production)

Abstract

The experiment was set up in 12 ponds of similar dimensions (5.0 x 9.0 x 1.2 m) in two periods of 60 days during summer and winter seasons in order to observe the effects of season and different mineral fertilization (N, P, NP, and control) associated to the organic one (rabbit manure) applied at 500 kg/ha.month dosis on the organic production of the ponds. Organic production was determined as seston volume sedimented, quantitative zooplankton rotifers and microcrustaceans in terms of number of organisms/L, and also the fish (common carp, Cyprinus carpio, and tilapia, Sarotherodon niloticus) productions, estimated through quarterly measurements and body weight determinations. It was observed a significant seasonal influence on pond's organic production and also that N fertilization enhanced faster fish growth and weight gain.