Growth of Largemouth Bass (LMB) as a food fish in Kentucky is constrained by a modest growing season. Understanding the relationship between temperature and growth is instrumental in developing a practical feeding protocol for LMB to take full advantage of growth potential throughout the year.
Two separate studies were conducted at different times over a 9-week period at the Aquaculture Research Center of Kentucky State University. In each study, seven recirculating systems with each system comprised of four replicate aquarium tanks were randomly assigned temperature treatments. Study 1 evaluated 15, 18, 21, 24, 27, 30, and 33 °C and Study 2 evaluated 9, 12, 15, 18, 21, 24, and 27 °C. Both studies utilized feed-trained juvenile LMB of the same size. The first study featured six fish per (tank size) tank (57.5±1 g), while the second study used 10 fish per tank (56.2±1.8 g). Fish were hand-fed once daily to apparent satiation using a slow-sinking 6.5 mm commercial trout feed (45% protein, 20% fat). Water quality was monitored weekly to ensure optimal conditions for growth. The batch weight of each treatment was recorded at stocking and harvest.
Regression analysis of the combined data (figure 1) revealed the following equation:
SGR = 0.0187 - 0.00367 C + 0.000243 C2 - 0.00000434 C3
where C is temperature (°C) and SGR is specific growth rate (%BW/day). Maximum SGR was 1.113 at 26.8 °C and R2 was 0.91. RTGI was created by assigning this maximum SGR a value of 100% and generating a data set across the temperature range for SGR values divided by 1.113. The resulting relationship creates an equation describing relative growth and temperature based on data from 60 g LMB (Figure 2): RTGI = 1.494 - (0.301 * T) + (0.0204 * T 2) - (0.000367 * T 3), where T is water temperature in degrees Celsius.