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

A study was conducted to determine the relationships between egg and newly hatched larvae sizes and growth and survival of Siberian sturgeon (Acipense r baeri) during early stages of development. We hypothesised that this may lead to improved rearing techniques and hatchery management. Eggs (mean siz e 2.8-4.1 nlm) were obtained from 20 cultured 13-14 years old females. Ther e was a positive correlation between egg size and total length (TL), body w eight (BW) and yolk sac volume of newly hatched larvae. Mortality during th e endogenous feeding phase were less than 3.6% and occurred among morpholog ically deformed fish. First feeding age (9-11 days post-hatch) correlated s ignificantly 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 fro m endogenous nutrition to exogenous feeding based on an artificial commerci al diet. Cannibalism was common between 9 and 15 days post-hatch, but was n ot an important source of larval mortality (2.0%-5.4%). Mortality substanti ally declined after the transition to exogenous feeding. Ar the end of the rearing period (20 days post-hatch), the effects of egg and newly hatched l arvae sizes were still evident on the TL and BW of larvae (P < 0.05). Howev er, no significant differences (P > 0.05) were found when larval specific g rowth rates (SGRs) were compared between progeny from different females, re vealing the ability of smaller specimens of Siberian sturgeon to grow at th e same rate as initially larger fish. Egg size did not provide any advantag e for survival of young fish (P > 0.05). We conclude that under generally f avourable rearing conditions, egg size has no direct implications for larva l survival of Siberian sturgeon. (C) 2000 Elsevier Science B.V. All rights reserved.