The interaction of temperature, salinity and body weight on growth rate and feed conversion rate in turbot (Scophthalmus maximus)

• We define the optimal temperature, salinity and body size for SGR and FCR.
• Using RSM to model the growth of turbot at different locations
• The optimal temperatures for SGR and FCR were lowest in full strength seawater.
• The model helpful in turbot farming at different geographic locations
• The optimum conditions of the maximum SGR and FCR: 20.88 °C/24.07‰/263.81 g

Response surface methodology (RSM) was used to determine the optimum processing conditions that give maximum specific growth rate (SGR) and food conversion rate (FCR). Temperature (17–25 °C), salinity (19‰–40‰), and body size (10–500 g) were the factors investigated. Experiments were designed according to the Box–Behnken Design with these three factors. The result shows that the coefficient of determination (R2 = 0.9991 for SGR and 0.9817 for FCR) and probability value (P < 0.0001) show significance for the regression model. In addition, interactions between temperature–salinity, temperature–body size of fish, and temperature–body size of fish on the growth were significant (P < 0.05), and those of temperature–body size on feed utilization were significant (P < 0.05). The optimum conditions to obtain the maximum specific surface area of SGR and FCR were temperature 20.88 °C, salinity 24.07‰, and body size 263.81 g, under which the maximal value reached 3.69%day− 1 and 0.869 respectively.