The physiology of juvenile shortnose sturgeon (Acipenser brevirostrum) during an acute saltwater challenge

Canadian Journal of Zoology, e-First Articles. One-year-old shortnose sturgeons (Acipenser brevirostrum LeSueur, 1818) were exposed to seawater (32 ppt) and brackish water (16 and 24 ppt) for 12, 24, 48, and 72 h and % body mass loss, plasma ions, energy metabolites, and oxygen-carrying variables were measured to evaluate survival and the physiological response to the acute salinity challenges. Survival in seawater was poor and plasma ion concentration was elevated in seawater. In sturgeons exposed to 24 ppt brackish water, ion concentrations remained elevated for 48 h, but began to decrease by 72 h. Fish exposed to 16 ppt brackish water did not show significant changes in ion concentrations over the 72 h period. Exposure to 32 ppt seawater resulted in significant and large decreases in body mass (about 20% –25%), whereas body mass loss was significantly less in fish exposed to 16 and 24 ppt brackish water. Overall, these findings suggest that juvenile sturgeons are able to tolerate lower salinities well but are less capable to endure higher salinities even on the short term (>48 h). These results suggest that juvenile A. brevirostrum could inhabit brackish environments earlier than previously expected, and that there appears to be a threshold at which salinity becomes a significant stress to these animals.
Source: Canadian Journal of Zoology - Category: Zoology Authors: Source Type: research