Paul Vanhaecke

International study on Artemia. 19. Hatching data for ten commercial sources of brine shrimp cysts and re-evaluation of the "hatching efficiency" concept.

Abstract A comparative hatching study has been carried out with Reference Artemia Cysts as well as cysts from Argentina, Australia, Brazil, Canada, France, Italy, the Peoples Republic of China, the Philippines and the U.S.A. Hatching rate, percentage and efficiency vary considerably from one cyst source to another. These hatching criteria are, however, not strainspecific since significant variation is found among cyst batches from the same geographical origin. The limitations of the “hatching efficiency” concept are discussed and a new criterion “hatching output”, i.e. the biomass of nauplii expressed in mg dry weight produced per gram cyst product, is proposed for evaluation of the hatching quality of Artemia cyst brands. The hatching quality of Reference Cysts and cysts from Canada and Argentina can be significantly improved by incubation of the cysts at low salinity. For almost all commercial sources the use of decapsulated cysts results in a significant increase of the hatching output.

Proposal for a short-term toxicity test with Artemia nauplii.

Abstract Although standardization of toxicity tests on aquatic organisms is an urgent necessity, very little has yet been achieved for the marine environment. As a first step in this direction, a simple, inexpensive and reliable short-term routine test with Artemia larvae is proposed. This test is the result of an extensive study in our laboratory, taking into account the advantages and disadvantages of Artemia bioassays published by various authors. The major advantage of the brine shrimp as a test species is its continuous availability under the form of dry cysts which can be hatched very easily; this eliminates all biological, technological, and financial problems of stock recruitment and/or culturing. The acute test presented is based on the determination of the LC50-24 hr of instar II–III nauplii of a specific Artemia strain. Presently this test is the subject of an intercalibration exercise in North America; an analogous exercise is now in progress in the European Economic Community countries.

International study on Artemia. XXXII. Combined effects of temperature and salinity on the survival of Artemia of various geographical origin

Abstract The brine shrimp inhabits geographically isolated biotopes with specific biotic and abiotic conditions. This has resulted in various geographical strains between which marked genetical, biological and chemical differentiation exists. The response of 13 different Artemia strains to the combined effect of temperature and salinity has been studied. Experimental temperatures tested ranged from 18 to 34°C and salinities from 5 to 120%.. Except for Chaplin Lake (itCanada) Artemia, all strains showed high survival over a wide range of salinities (35–110%.). For all strains the common temperature optimum was between 20 and 25°C. Interaction 7between temperature and salinity was negligible or very limited. Substantial differences in tolerance were recorded in particular at the lower end of the range of experimental salinities and at the upper end of the range of temperatures. Resistance to high temperature seems to be related to the genetic classification of the Artemia strains in different sibling species. Differences, however, also exist among strains from the same sibling species. Genetic adaptation to high temperature seems to take place in Artemia. The data obtained provide a first guideline for strain selection for specific aquacultural purposes.

International study on Artemia XXIV. Cold storage of live Artemia nauplii from various geographical sources: Potentials and limits in aquaculture☆

Abstract Freshly-hatched Artemia nauplii from various geographical sources survived storage in a refrigerator (2–4°C) at densities of 2000 per ml and above. Except for Artemia from Chaplin Lake and Buenos Aires, naupliar viability was very high even after 48 h storage, and did not decrease significantly after a 24 h post-storage transfer to 25°C. Neither the naupliar dry weight nor biochemical composition changed significantly during refrigeration for most strains tested. Comparative culture-tests with stored and freshly-hatched nauplii as food for juvenile marine mysids Mysidopsis bahia M. and larval carp Cyprinus carpio L. revealed similar production performances.

Quality evaluation of brine shrimp Artemia cysts produced in Asian salt ponds

Artemia cysts produced in inoculated salt ponds in the Philippines, Thailand and India, were analyzed in comparison with the parental strains used for the inoculations. Cyst hatching efficiency, hatching rate and color changed significantly after inoculation, whereas the cysts diameters, nauplius survival and nauplius growth remained fairly constant. The nutritional value of the Artemia nauplii was determined in a standard culture test with Mysidopsis bahia juveniles as test animals. Production results were compared with the fatty acid profiles of the Artemia nauplii. Low levels of the essential fatty acid 20:5ω3 in one of the produced cyst batches were probably caused by inadequate food conditions in the pond and resulted in poorer growth of the Mysidopsis juveniles. Based on the results of this study a distinction is made between essential and nonessential strain selection-criteria for Artemia inoculations and transplantations.

International study on Artemia XXX. Bio-economic evaluation of the nutritional value for carp (Cyprinus carpio L.) larvae of nine Artemia strains

Abstract The nutritional value of freshly hatched nauplii from nine geographical strains of brine shrimp, Artemia, was determined for larvae of the carp (Cyprinus carpio). After 2 weeks of culture, the survival of carp larvae was over 90% and no significant differences in survival among treatments were detected. The growth rate of the larvae, however, was a function of the Artemia strain used. The highest weight gains were recorded with parthenogenetic Artemia, the lowest with Chaplin Lake brine shrimp and intermediate results with the other bisexual strains. With the exception of the Chaplin Lake strain, the growth results were positively correlated with the size and weight of the nauplii used. A bio-economic study revealed that although all Artemia strains supported good survival and growth in carp larvae, the selection of specific cyst sources may result in important savings of Artemia cyst use in aquaculture hatcheries.