Abstract or Keywords
The Florida stone crab occupies habitats that can experience a range of salinities throughout the year, yet nothing is known about their salt balance physiology. We acclimated stone crabs for a week to conditions that mimic the range of salinities they experience in coastal habitats to determine their ability to regulate or conform their hemolymph osmolality and chloride ion concentration. At a salinity of 35 ppt or higher, the hemolymph osmolality mirrored the treatment seawater indicating that crabs were osmoconforming. Stone crabs physiologically shifted to being osmoregulators in the lowest salinities (20 and 25 ppt). Similarly, crabs switched from being chloride ion conformers at higher salinity to chloride ion regulators at salinities of 20 and 25 ppt. The ability of stone crabs to physiologically shift from being conformers to regulators is important for predicting how the species may respond to future changes in salinity associated with freshwater runoff or hypersaline events that are triggered by marine heat waves.