Overwintering Survival and Relative Mortality of Young of the Year Black Sea Bass in Coastal Areas in the Northeast US

Black Sea Bass Centropristis striata is a recreationally and commercially significant species that ranges from the Gulf of Maine to Florida, with two stocks separated by Cape Hatteras. In the northern stock, seasonal temperature variability elicits a seasonal offshore and southward migration that is not observed in the southern stock. At the northern edge of its range, the ability of juvenile Black Sea Bass to survive winter depends upon the timing and extent of their seasonal migration offshore to escape cooler nearshore waters and their ability to survive cool water temperatures. Increased winter survival of juveniles has the potential to allow this species to establish populations in waters where they have previously existed at low abundances. To estimate the survivorship of Black Sea Bass during winter months, an overwintering experiment was conducted. Young-of-the-year Black sea bass collected from Great South Bay, New York between September and October 2013 (n=210) were exposed to four temperatures (12, 10, 8 and 6°C) and two salinities (34 and 29 ppt). A survivorship analysis was used to determine mortality rates among treatments and to identify the relative overwintering mortality in different coastal areas in the Northeast US.

Keywords: Black Sea Bass, survivorship analysis