The use of <i>Artemia</i> in marine fish larviculture

Among the live diets used in the larviculture of fish and shellfish, the brine shrimp Artemia nauplii constitute the most widely used food item; i.e., over 700 metric tons of dry Artemia cysts are annually marketed worldwide for on-site hatching into 0.4 mm nauplii.Although the use of Artemia appears to be simple, considerable progress has been made in the past decade in improving and increasing its value as a larval diet for marine fish larvae. The improvements include: identification of the most appropriate strains and batches; new techniques for cyst disinfection; decapsulation and hatching; and enrichment and cold storage of nauplii. Using particulate or emulsified products rich in highly unsaturated fatty acids or n-3 HUFAs, the nutritional quality of Artemia can be further tailored to suit the predators' requirements by bio-encapsulating specific amounts of these products in the Artemia metanauplii. Application of the method of bioencapsulation, also called Artemia enrichment or boosting, has had a major impact on larviculture output, not only in terms of survival, growth and success of metamorphosis of the fish, but also with regard to their quality, e.g., reduced malformations, improved pigmentation and increased stress-resistance. Nonetheless, in many species survival rates are still marginal.For several marine fish species, the optimal dietary levels of n-3 HUFAs are still not met by enriched Artemia . Furthermore, while n-3 HUFAs might have proven most critical, it is very likely that other nutrients (e.g., other lipid classes, vitamins and free amino acids) might appear equally important and in some species even more critical. The bio-encapsulation technique can also be used for the oral delivery of hormones and therapeutics to the fish larvae. Artemia juveniles, grown to a size that suits the feeding behaviour of the growing predator and/or adult biomass collected from local saltworks or mass production units, can be used as an excellent nursery and weaning diet for most species of marine fish, eventually reducing fish mortalities, cannibalism and heterogeneous growth