1Graduate School of Biosciences and Biotechnology, Fukui Prefectural University, Obama, Fukui 917-0003, Japan, 2Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, Windsor, Ontario, N9B 3P4, Canada
Ontogenetic changes in physiological tolerance during larval development of Japanese flounder Paralichthys olivaceus were examined relative to a variety of environmental stresses as follows: freshwater, high salinity (salinity range: 30-55), high water temperature (temperature range: 20-36°C) and formalin (concentration range: 0-0.6%). Highest stress tolerance was shown by newly hatched larvae (1 day after hatching), and then decreased drastically until 10 days after hatching. We considered that the high sensitivity to external environmental stresses at 10 days after hatching was caused by the development of the mouth and opercula. Patterns of tolerance change during the early life stages differed depending on the environmental stresses.