The silver cat¢sh, Rhamdia quelen, is endemic to North, Central and South America with high aquaculture potential and wide acceptance in the market. Breeder ¢sh were subjected to induced reproduction through hypophysation using a crude common carp pituitary extract. Egg characteristics, oocyte surface ultrastructure and histology of larval ontogenesis until whole yolk resorption were described for the ¢rst time for this species. Oocytes and semen were obtained by manual extrusion, and fertilization was conducted using the dry method. After fertilization, eggs were kept in incubators at 24 1C. The embryonic development was monitored using a stereomicroscope every 10 min until hatching. To analyse the larval development, larvae samples were collected from incubators daily until the ¢fth day, ¢xed in Bouin's £uid and subjected to routine histological techniques. The oocyte extrusion occurred 8 h after the second hormone dose at 26 1C. The oocytes were spherical, non-adhesive and yellow, with a diameter of 1471.75 AE 47.63 mm. Scanning electron microscopy revealed a thin jelly coat covering the zona radiata in the animal pole around the micropyle. The blastopore closure occurred within 8 h after fertilization, and the fertilization rate was 79.9 AE 5.2% at 24 1C. Embryonic development was completed within 25 h 30 min after fertilization. The complete resorption of the yolk and the formation of the digestive system organs and the mouth opening occurred on the ¢fth day, indicating a need for exogen-ous feeding. The results of this study provide information important for improvement in R. quelen culture and management. Early development of silver cat¢sh M P deAmorim et al. Early development of silver cat¢sh M P deAmorim et al.

Modo de acesso: World Wide Web Inclui bibliografia 1. Gestão Econômica 2. Custos. 3. Finanças I. Título CDD-658.8O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos seus respectivos autores.

Modo de acesso: World Wide Web Inclui bibliografia 1. Gestão 2. Qualidade. 3. Melhoria I. Título CDD-658.8O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos seus respectivos autores.