Studies on Factors Related to Mortality of Young Red Seabream (Pagrus major) in the Artificial Seed Production

Abstract

Infection tests were attempted to clarify various conditions which precipitated diseases of young red seabreams. Vibrio alginolyticus CY-1 isolated from diseased fish in 1975 was used for the tests.
Young red seabreams showed signs of disease both in the water containing V. alginolyticus and in the one with the bacteria and Rotifera. Higher mortality occurred in the latter case.
Red seabreams reared in the seawater with the bacteria and Chlorella had a higher surviving rate than those in the seawater without Chlorella. It was observed through other experiments that V. alginolyticus in the sea water with both Rotifera and Chlorella tended to increase in number as the number of Chlorella was decreased by the consumption of Rotifera.