Influence of egg size on growth and survival of early stages of Siberian sturgeon ž / Acipenser baeri under small scale hatchery conditions

A study was conducted to determine the relationships between egg and newly hatched larvae Ž . sizes and growth and survival of Siberian sturgeon Acipenser baeri during early stages of development. We hypothesised that this may lead to improved rearing techniques and hatchery Ž . management. Eggs mean size 2.8–4.1 mm were obtained from 20 cultured 13–14 years old Ž . females. There was a positive correlation between egg size and total length TL , body weight Ž . BW and yolk sac volume of newly hatched larvae. Mortality during the endogenous feeding phase were less than 3.6% and occurred among morphologically deformed fish. First feeding age Ž . Ž . 9–11 days post-hatch correlated significantly with egg and newly hatched larvae size P-0.05 . At the onset of the exogenous feeding, mortality sharply increased in all experimental groups and represented 2.1%–23.5%. Losses were attributed to the change from endogenous nutrition to exogenous feeding based on an artificial commercial diet. Cannibalism was common between 9 Ž . and 15 days post-hatch, but was not an important source of larval mortality 2.0%–5.4% . Mortality substantially declined after the transition to exogenous feeding. At the end of the rearing Ž . period 20 days post-hatch , the effects of egg and newly hatched larvae sizes were still evident on Ž . Ž . the TL and BW of larvae P-0.05 . However, no significant differences P)0.05 were found Ž . when larval specific growth rates SGRs were compared between progeny from different females, revealing the ability of smaller specimens of Siberian sturgeon to grow at the same rate as initially Ž . larger fish. Egg size did not provide any advantage for survival of young fish P)0.05 . We ) Corresponding author. Tel.: q34-934-021-447; fax: q34-934-021-93; e-mail: [email protected] 0044-8486r00r$ see front matter q 2000 Elsevier Science B.V. All rights reserved. Ž . PII: S0044-8486 99 00287-2 ( ) E. Gisbert et al.rAquaculture 183 2000 83–94 84 conclude that under generally favourable rearing conditions, egg size has no direct implications for larval survival of Siberian sturgeon. q 2000 Elsevier Science B.V. All rights reserved.