The salinity in one of the ISO tanks was then increased over the next 6 hr to 75% SW (25‰). An initial attempt to acclimate fish to 100% SW (34‰) over 30 hr resulted in 92% mortality. Previous studies have shown that O. mossambicus cannot tolerate an abrupt transfer from FW to full-strength SW, and require a gradual (1 week) acclimation period [see review in