Osmoregulatory Evaluation of the Seminole Killifish after Gradual Seawater Acclimation

Aquaculture of marine baitfish species is still in its relative infancy and the increasing value of coastal property is forcing marine aquaculture inland. The Seminole killifish Fundulus seminolis, a freshwater species that is endemic to Florida, has recently emerged as a candidate for marine baitfish aquaculture. Gradual acclimation of Seminole killifish from 0-g/L salinity to natural seawater at 32-g/L salinity was carried out over 24, 48, 72, and 96 h. Physiological analyses of seawater-acclimated fish yielded elevated plasma ion (sodium, potassium, chloride) and osmolality concentrations accompanied by decreases in body weight and muscle water content. Although all of the seawater-acclimated physiological endpoints measured remained significantly different from control values, a general trend signaling the initiation of osmoregulatory compensation was noticed in 96-h values as select analytes began to migrate towards reference values derived from controls. Results of this investigation will contribute to the development of salinity acclimation protocols for use in commercial aquaculture as well as marketing and distribution strategies for the economically valuable Seminole killifish