Study on the embryonic and early larval development of Siniperca scherzeri

Siniperca scherzeri,one of the most important economic freshwater fishes,is distributed in China widely. In recent decades,the resources of Siniperca scherzeri declined rapidly because of the deterioration of ecological enviroments and excessive catching. In order to protect and exploit it reasonably,the artificial propagation was conducted in Fujian province. The fertilized eggs were obtained by injecting interior hormone into the parent female fish and using artificial dry-fertilization,and were hatched at temperature 20 ℃. The development of embryo and larva of Siniperca scherzeri was observed consecutively. The morphological features and development characteristics of Siniperca scherzeri were described during the embryo and larva stages. The adhesive eggs were found to be about glutinous,light yellow in color,and( 1. 76 ± 0. 08) mm in diameter,and grew( 2. 20 ± 0. 09) mm 5 min after fertilization and inflation. When water temperature was 20 ℃,the hatching time was 189. 33 h,and the newly hatched larvae had mean total length( 5. 57 ± 0. 18) mm and phototaxis. At the water temperature 24 ℃,the larvae began feeding when 3 days old and entered the mixed nutrition stage and the phototaxis disappeared. The yolk-sac exhausted when 5 days old,their oil globes were absorbed completely at the 6 days old when larvae came into the stage of nutrition outside completely. There was an extremely significant linear relationship between total length and age: y = 0. 4916x + 5. 7209( P 0. 01).