Effects of temperature on growth and metabolism in a Mediterranean population of European sea bass, Dicentrarchus labrax

Growth and metabolism of juvenile European sea bass of a Western Mediterranean population were assessed at six constant temperatures (13, 16, 19, 22, 25 or 29 degreesC) in an 84-day trial. Duplicated groups of 84 fish (initial weight 80 I g) were held under O-2-concentrations close to saturation (87 mg l(-1)) and were fed to satiation. Mass gain increased as temperature increased from 13 to 25 degreesC. At 25 and 29 degreesC, growth was similar up to day 72, but a 6% decrease was observed by day 84 at 29 degreesC. Days 0-84 specific growth rates (SGR) were 0.45%,1.29% and 1.21% day(-1) at 13, 25 and 29 degreesC, respectively. The estimated temperature (7) for maximum SGR was 26 degreesC (SGR = 1.715 - 0.322T + 0.022T(2) - 4.233e(-4)T(3)). Feed intake (FI) increased with temperature being 1.45-1.46% day(-1) at 25-29 degreesC and the estimated temperature for maximum FI was 27.5 degreesC (FI = 1.453 - 0.214T+0.016T(2) - 2.916e(-4)T(3)). Feed efficiency (FE) averaged 1.01-1.04 at 1925 degreesC, was lower at 16 and 13 degreesC (0.9) and maximum FE was estimated to occur at 24 degreesC (FE = 1.318 - 0.103T+7,174T(2) - 1.395T(3)). The main difference in fish body composition related to temperature was a higher crude fat concentration at 13 - 16 degreesC at the end of the experiment (day 84). Protein retention was 38% (g g(-1)) at 25 degreesC (NS differences in 22-28 degreesC range). Ammonia excretion (TAN, mg N kg(-1) day(-1)) was positively correlated to temperature as it was dependent on feeding rate (FR, g kg(-1) day) (TAN=-496.5 FR+24.4 FR2+2685). O-2-consumption (MO2R, mg kg(-1) h(-1)) was influenced by temperature (MO2R=10.83T+4.48) and by FR (MO2R=-206.8FR+10.6FR(2)+1142). (C) 2004 Elsevier B.V All rights reserved.