Temperature and Salinity Effects on Survival and Growth of Early Life Stage Shubenacadie River Striped Bass

Abstract

A series of short, laboratory‐based trials was conducted on striped bass Morone saxatilis from the Shubenacadie River, Nova Scotia, Canada, starting with wild‐caught eggs and proceeding through to the early juvenile stage. The levels of the experimental factors—salinity (0–35‰) and temperature (10–30°C)—spanned the range occurring in the natal estuary. Survival of eggs to 1 d posthatch (dph) was highest, more than 60%, between 2‰ and 20‰ salinity and was reduced significantly (to <50%) only in salinities of 30‰ or greater. Similarly, survival of prefeeding larvae was reduced only at salinities above 30‰, suggesting that their salinity tolerance is higher than that of U.S. populations. Moreover, 1–7‐dph larvae were tolerant to temperature decreases that are lethal to other populations, with around 40% surviving between 10°C and 14°C at intermediate salinities. Older, 23‐dph larvae were less tolerant to cold, with fewer than 20% surviving 7 d at 10°C, but these larvae thrived at high temperature, exhibiting highest survival and growth at 26°C across salinities from 1‰ to 35‰. Growth of early juvenile stages (55–104 dph) was independent of salinity (1–30‰) and was highest between 26°C and 30°C, suggesting a temperature optimum similar to that of U.S. populations.