Reduction in Occurrence Frequency of Albinism in Juvenile Flounder Paralichthys olivaceus Hatchery-reared on Wild Zooplankton

Abstract

The effect of a wild zooplankton supply on the appearance of albinism in juvenile flounder P. olivaceus was studied by two rearing experiments. Flounder larvae were initially reared with only rotifer Brachionus plicatilis and then given wild zooplankton and rotifer or only wild zooplankton, from 5.50-5.57 mm TL to complete metamorphosis. These were compared with those given Brazilian Artemia salina nauplii and rotifer during the same stage. Larvae given wild zooplankton showed poorer growth and lower survival rate than those given Artemia. However the frequency occurrence of albinism in the former was very much lower (0.1 -1.8%) than in the latter (97.2-100.0%). When flounder larvae were given wild zooplankton and rotifer, they took 40.0-76.3% rotifer in number during pelagic stage, These results suggested the possibility of preventing albinism through the improvement of cultured foods during early life stage. © 1985, The Japanese Society of Fisheries Science. All rights reserved.