The elusive copepods: their production and suitability in marine aquaculture

摘要

Despite the fact that the suitability of copepods as live prey for marine fish larvae is now well established, their use in aquaculture remains sporadic. Although of lower nutritional value, the relative ease of production of rotifers (Brachionus spp.) and Artemia nauplii continues to ensure their predominance. Studies in the literature have highlighted differences in the levels and ratios of fatty acids, lipid classes and pigments between copepods and traditional live prey. Such differences may have important consequences for fish larval nutrition. The consequences of poor nutrition during fish larval development may be obvious, for example deformities or malpigmentation. but in many cases may be obscure, as in affects on temperature tolerance or growth during later life stages. In some aquaculture systems, copepods are cultured in large quantities in outdoor, extensive or semi-intensive units. Intensive-rearing systems for copepods require further development. However, it is now established that intensive rearing on monoalgal diets does not result in severe deterioration of the nutritional value of the copepods, at least in terms of their highly unsaturated fatty acid (HUFA) content. In some cases, the provision of copepods for a short periodof time during the larval stage is sufficient to ensure normal development. However, it remains to be demonstrated that the extra costs involved result in increased profits as a result of higher percentages of normally pigmented juvenile fish, improvedgrowth and survival and reduced incidence of disease. This paper reviews the advances in production systems for copepods, their nutritional value as live prey for fish and their present and potential use in aquaculture.