The effect of temperature on the metabolic and ventilation rate of southern striped bass (Morone saxatilis)

NSF fellow: Kathleen Brewster, Christopher Newport University

Mentor: Dr. Johanne Lewis

We assessed the effect of temperature and hypoxia tolerance on southern striped bass that are no longer self-sustaining in the Savannah River. We acclimated 8 fish at 17 degrees Celsius, tested their standard metabolic rate (SMR) and maximum metabolic rate (MMR) and then subtracted the MMR from the SMR to get the aerobic scope. We used the aerobic scope obtained determine the ideal temperature for the southern striped bass population. Fish were placed in an intermittent flow respirometer and trialed after working them out to obtain their maximum metabolic rate and then the next day we tested their standard metabolic rate. To test their hypoxia tolerance, we closed off the respirometry chamber and allowed them to bring down their oxygen in their tank. At each oxygen interval, we took a one-minute video of the fish and tracked their ventilation rate for 17 and 25 degrees Celsius. We found that the fish had the highest aerobic scope at ~20 degrees Celsius. Additionally, 25 degrees Celsius fish had an unexpectedly low aerobic scope. This low aerobic scope could be due to a switch point of biologically adapting to survive in warmer water, but more research is needed to confirm this finding. However, this switch point could be a reason for the irregular results and a high mortality rate with these fish. Our study showed that the ventilation rate had no statistically significant difference until the dissolved oxygen reached <3 mg/L, affirming the fish had a high hypoxia tolerance at both 17 and 25 degrees Celsius.