Influence of composition of Brachionus plicatilis and Artemia on growth of larval sablefish ( Anoplopoma fimbria Pallas)

Abstract

Larval sablefish, Anoplopoma fimbria, were fed rotifers, Brachionus plicatilis, and later brine shrimp, Artemia, reared on the microalgae, Nannochloropsis oculata, Isochrysis galbana (T-Iso) and Chroomonas salina. Diet composition significantly influenced growth and time to 50% mortality of larvae. Survival was greatest for the group fed zooplankton reared on N. oculata and least in the group reared on C. salina. Protein content was significantly higher in rotifers reared on I. galbana (T-Iso) than on the other algae, but was not correlated with larval growth or survival. Lipid content of rotifers was independent of algal species used in production. Carbohydrate was highest in rotifers fed N. oculata and may have influenced the survival of sablefish larvae. Contents of protein, lipids and carbohydrate in Artemia reared on different algae were not significantly different, minimizing any influence on growth and development of the larvae. Contents of constituent fatty acids in rotifers, but not Artemia, were the major differences in these dietary plankton fed to fish larvae. B. plicatilis contained 15% 20:5 n−3 (EPA) and 0.3% 22:6 n−3 (DHA) when reared on N. oculata, 3.3% EPA and 5.2% DHA when reared on I. galbana (T-Iso) and 5.6% EPA and 3.0% DHA when reared on C. salina. The failure to rear the larvae beyond day 60 from first feeding and the observed 50% n−3 HUFA in lipid of sablefish eggs and pelagic zooplankton, suggests that the dietary HUFA levels used to feed larvae in this study were too low to meet the apparent HUFA requirement.