Suitability of reservoirs for hybrid striped bass: Insights from an experimental evaluation of temperature and dissolved oxygen effects on consumption, growth, and condition

Highly productive reservoirs, such as those found in Ohio, can provide hostile environments during summer when epilimenetic temperatures can be high (> 30°C) and metalimnetic and hypolimnetic dissolved oxygen levels low (0 to 50% saturation).  These conditions may be especially problematic for fishes with a lower optimal temperature for growth, which oftentimes might only be found in the hypoxic hypolimnion.  As part of a larger research effort designed to explore the suitability of Ohio reservoirs for expansion of a hybrid striped bass (Morone saxatilis x M. chrysops) stocking program, we conducted laboratory experiments to quantify how temperature and dissolved oxygen influence hybrid striped bass respiration, consumption, growth, and condition (e.g., energy density, lipid content, hepatosomatic index).  Experiments were conducted in a 4x3x2 factorial design (n=4 replicates/treatment) at four temperatures (15, 22, 27, and 30°C) and three dissolved oxygen levels (30, 50, and 80% saturation), using two sizes of juvenile fish (50g and 100g).  Beyond detailing our experimental results, we combine them with spatially-explicit field observations of temperature, dissolved oxygen, and prey biomass (i.e., gizzard shad Dorosoma cepedianum) from Ohio reservoirs of contrasting productivity and depth to discuss their suitability for hybrid striped bass growth.