Fish Physiology — Osmoregulation
To obtain a greater understanding of the osmoregulatory ability and habitat use of Atlantic sturgeon at early life stages, we examined whether salinity is a limiting factor for juveniles (2 months old). Juvenile Atlantic sturgeon were acclimated to one of three salinity treatments (0, 10, 33 ppt) representing the range of salinity they would be expected to encounter. Growth was measured over the proceeding 6 months and osmoregulatory ability, quantified by blood plasma osmolality and ionic concentrations, was measured after 4 months. All fish grew but fish in the 0 and 10 ppt treatments grew more than fish in 33 ppt. Blood plasma osmolality was regulated at similar levels regardless of salinity. Therefore, juvenile Atlantic sturgeon have the physiological capability to move between salinity habitats, but grow
faster in low salinities.