and/or ecological changes in this lake, which has been illustrated by the unusually low cyst
harvests in the seasons 1993-1994 and mainly 1994-1995.
Already in the late 1970s it appeared that the nutritional value of Artemia, especially for
marine organisms, was not constant but varied among strains and within batches of each
strain, causing unreliable outputs in marine larviculture. Through multidisciplinary studies in
the 1980s both the causes for the nutritional variability in Artemia and the methods to
improve poor-quality Artemia were identified. Genotypic and phenotypic variation (i.e. cyst
size, cyst hatching characteristics, caloric content and fatty acid composition of the nauplii)
determine if a particular cyst product is suitable for hatchery use of specific fish or shrimp
species.
By bio-encapsulating specific amounts of particulate or emulsified products rich in highly
unsaturated fatty acids in the brine shrimp metanauplii, the nutritional quality of the Artemia
can be further tailored to suit the predators' requirements. Application of this method of bioencapsulation,
also called Artemia enrichment or boosting, has had a major impact on
improved larviculture outputs, not only in terms of survival, growth and success of
metamorphosis of many species of fish and crustaceans, but also with regard to their quality,
e.g. reduced incidence of malformations, improved pigmentation and stress resistance. The
same bio-encapsulation method is now being developed for oral delivery of vitamins,
chemotherapeutics and vaccines.
Furthermore, a better knowledge of the biology of Artemia was at the origin of the
development of other Artemia products, such as disinfected and decapsulated cysts, various
biomass preparates, which presently have application in hatchery, nursery and broodstock
rearing. All these developments resulted in optimized and cost-effective applications of this
live food in hatchery production.