Effects of feeding with frozen freshwater cladoceran Moina macrocopa on the performance of red sea bream Pagrus major larviculture

The feeding effects of freshwater cladoceran Moina macrocopa to the larvae and juveniles of red sea bream were investigated. M. macrocopa was mass-cultured with freshwater Chlorella as feed and was enriched nutritionally with a commercial enrichment diet. Because M. macrocopa die in seawater within a few minutes, the cladocerans were frozen after nutritional enrichment. The survival rates, growth rates and stress tolerances of fish fed with enriched M. macrocopa were compared with those fed with enriched Artemia and with zooplankton harvested from open seawater. The fatty acid composition of each type of zooplankton was analyzed. Mass-cultured M. macrocopa could be enriched with a commercial enrichment diet. The DHA/EPA ratio of M. macrocopa was inferior to that of enriched Artemia nauplii and wild zooplankton. Although the growth and stress tolerance of fish fed on frozen M. macrocopa were inferior to those fed with enriched Artemia nauplii and wild zooplankton, their survival rate was superior. It was concluded that frozen and enriched M. macrocopa could be fed to red sea bream larvae and juveniles. However, it is necessary to improve its fatty acid composition, particularly the DHA content.