Abstract
The endangered amphidromous goby, Rhinogobius sp.BI, is the only freshwater fish endemic to the Bonin islands. Ex situ aquaculture, conducted over a number of generations, should be undertaken so as to ensure future protection of the species. Salinity being one of the most important larval-rearing factors, experiment was conducted on the salinity tolerance of hatching larvae. These could generally survive for 72 hours under any salinity conditions. However, all individuals died after 144 hours in 100% artificial seawater, whereas over 60% survived for a longer term in freshwater and 50% artificial seawater. With decreasing salinity, the greater the survival duration time. However, larval numbers fell dramatically ca. 40 days after hatching in 50% artificial seawater, such a reduction in number indicating a critical depletion period in the early developmental stages.
