The impact of acute salinity exposure and temperature on the survival, osmoregulation, and hematology of juvenile shortnose sturgeon (Acipenser brevirostrum)

Canadian Journal of Zoology, e-First Articles. Juvenile shortnose sturgeon (Acipenser brevirostrum Lesueur, 1818) were exposed to seawater and freshwater for 24 h to evaluate the osmoregulatory capabilities over a seasonal temperature gradient (5, 10, 15, 20 °C). Additionally, juveniles were exposed to 5 °C seawater and freshwater over 72 h to evaluate survival and osmoregulatory capacity under cold water conditions. Osmoregulatory capability was evaluated using standard metrics: survival rate, mass loss, plasma chloride ion (Cl–) concentrations, os molality, oxygen-carrying variables, and energy metabolites. Three mortalities occurred following 24 h exposure to 20 °C seawater (73% survival) and one mortality occurred within 72 h in 5 °C seawater (89% survival). Plasma Cl– concentrations and osmolality were elevated in seawater-exposed juve niles at every exposure time, regardless of temperature. The least mass was lost in juveniles exposed to 5 and 10 °C seawater, versus 15 and 20 °C seawater. Low mass loss is likely due to a lower metabolic rate and lower ventilation, which would slow the rate by which osmotic stress would occur un der cold conditions.
Source: Canadian Journal of Zoology - Category: Zoology Authors: Source Type: research