Effects of egg size on growth and survival of early stages of Persian sturgeon (Acipenser persicus) larvae

摘要

It is important for the culture of Acipenser persicus to study the potential factors that influence growth and survival of early stages, particulary the egg size. Millions of sturgeon fingerlings that are produced at different sturgeon propagation centers are released into rivers terminating at the Caspian Sea, north east of Iran, every year. Sturgeon fingerling production is considered to be one of the most difficult phases of hatchery rearing. Egg size and development may affect their quality, ability to produce viable larvae and to some extent directly determine growth and survival of young fish (Heming and Buddington 1988, Kjorsvik et al. 1990). The ability of larval fish to cope with adverse abiotic conditions, such as temperature, salinity and water currents and biotic conditions of starvation, competition and predation depend on a number of factors including body size, available energy resources, swimming ability and reactive distance (Miller et al. 1988, Fritz et al. 1990). Body size is an important variable influencing the physiology, ecology and behavior of larval fish (Peters 1983, Miller et al. 1988). The ability of smaller larvae to feed successfully is constrained because they have shorter reaction distances and restricted swimming abilities (Blaxter 1986, Webb and Weihs 1986). Swimming ability, largely determined by body size (Webb and Weihs 1986), also influences the ability of larval fish to maintain their position in optimal areas for growth and survival.