Interactive Effects of Hypoxia and Temperature on Consumption, Growth, and Condition of Juvenile Hybrid Striped Bass

Productive tributary reservoirs can become suboptimal environments for fish during summer because of hypolimnetic hypoxia (<= 3 mg O-2/L) and high epilimnetic temperatures that reduce access to quality habitat for growth. We conducted a laboratory experiment using a 3 x 3 x 2 (temperature x dissolved oxygen [DO] x fish size) complete factorial design to examine the effect of DO concentration and temperature on consumption, growth, and proximal body composition of juvenile hybrid Striped Bass (Striped Bass Morone saxatilis x White Bass M. chrysops), which are commonly stocked into North American reservoirs and for which tolerances to environmental conditions are not fully known. Our study demonstrates that consumption and growth of juvenile hybrid Striped Bass were affected by an interaction between temperature and DO. Specifically, low DO conditions negatively affected consumption, especially at high temperatures. By contrast, growth was largely unaffected by DO, except at high temperatures when low DO reduced fish growth. Temperature and DO did not interact to cause changes in energy density or moisture content, although temperature did independently affect the moisture content of hybrid Striped Bass tissues. The change in moisture content was lowest for fish exposed to high temperatures, suggesting a negative effect of temperature on fish condition. Collectively, our experimental findings provide useful information for modeling the energetics of hybrid Striped Bass and assessing reservoir habitat quality, which can help guide decision making regarding stocking.