Desempenho de juvenis de robalo-flecha e robalo-peva submetidos a diferentes densidades de estocagem em água doce

Abstract

The objective of this experiment was to compare survival and growth of fat snook(Centropomusparallelus) and common snook (Centropomusundecimalis), reared in freshwater under different stocking densities. The experiment lasted 251 days. The fish were randomly distributed in cages (1 m x 1 m x 0.8 m), treatments in triplicate, placed inside an earthen pond located in Camboriu (SC). Water quality parameters were measured and were adequate for the species, except for the low temperatures (19.8 ± 3.3 °C). Zootechnical parameters were analyzed by a two-way ANOVA (species x density). Concerning growth, total length and condition factor were significantly different between species, and specific growth rate was not significantly different between treatments (0.23% day-1). Nevertheless, there was a significant interaction of species and stocking density in relation to final weight (fat snook 42.4 ± 16.8; 34.5 ± 15.3 e 39.1 ± 18.7 g; common snook 46.2 ± 18.3; 52.8 ± 22.6 e 46.4 ± 18.8 g; for 12.5; 25.0 and 37.5 fish m-³, respectively). Regarding survival, there was also a significantly difference between species (fat snook 90.0 ± 5.9% and common snook 66.3 ± 9.4%). Stocking density significantly affected biomass only (459 ± 74.5 g; 842 ± 100 g; 1,157 ± 293 g, in densities of 12.5; 25.0 e 37.5 fish m-³, respectively). Both species had a positive growth without a clear advantage for common snook, as expected.