Manejo de Matrizes e Acompanhamento da Biologia Reprodutiva da Pescada branca Plagioscion squamosissimus (Hackel, 1840) em Tanque- rede na Comunidade do Catalão no Município de Iranduba (Amazonas- Brasil)

Abstract

The first time grow out and managing freshwater silver croaker, Plagioscion squamossimus, in cage culture was carried out from January to December 2008 near the confluence of Rio Negro and Rio Solimões on the margin of Catalão Island near Manaus, Amazonas, Brazil. A total of 130 silver croakers were captured on site and stocked in three culture cages, measuring 3 x 2 x 2m with a density of 3.6 fishes/m³. The first year mortality of captive fishes was 10.7%, while the initial stock had a mean size of 29.5 cm SL and weighed 536 g; the final mean size of 34.8 cm SL and weighed 812 g were obtained from 82 fish. Sex dimorphism was found in silver croakers during maturation. Pelvic and anal fins of female turned into bright pink and emitted distinct clicking sound from that of croaking in males. Sex ratio was two females for one male, but fishes greater than 37 cm SL were all females. Gonad Somatic Index was highest in February with an estimate fecundity of 243 thousand eggs for females 35cm. Results of the study constituted a technical basis for silver croaker cage culture, which can be put in practice for rural communities and a new strategy for aquaculture in the Amazon.