Influence of three geographically different strains of Artemia nauplii on occurrence of albinism in hatchery-reared flounder Paralichthys olivaceus.

Abstract

Three geographically different strains of Artemia (Brazil 1981, Tien-tsin; China 1981 and San Francisco Bay; USA 1981) were used in this study, Chemical components of these 3 strains of Artemia were analyzed and the influences of their nauplii on occurrence of albinism in hatchery -reared Paralichthys olivaceus were examined. Larval flounder of 9-10 days post-hatching (5.50±0.32mm TL) which had been fed initially with only rotifers were given one of 3 different strains of Artemia nauplii mixed with rotifers until the flounder's completion of metamorphosis. Then the percentage occurrence of albinism was compared among 3 groups of flounder (BA, TA and SA) fed respectively on Artemia nauplii in Brazil, Tien-tsin and San Francisco. The percentage occurrence of albinism was highest (99.5-100.0%) in BA, intermediate (81.3-84.6%) in TA and lowest (21.1-26.1%) in SA. Population density, feeding level and the other rearing conditions in BA were almost the same as those in SA. These results suggest a close relationship between some chemical components of Artemia nauplii and the occurrence of albinism in flounder. However, principal factors in Artemia responsible for abnormal coloration were not specified from the difference of chemical components among these 3 different strains in terms of minerals, heavy metals, lipid class, fatty acids and residual pesticides.