Influence de la température sur la consommation d'oxygène du bar juvénile, Dicentrarchus labrax L.

This study quantifies the influence of temperature on the respiratory activity of juvenile Dicentrarchus labrax L. The fry were less than one year old and were obtained from the breeding tanks at the C.O.B. (Centre Océanologique de Bretagne). Diminution in the oxygen concentration, during time, within sealed ves­sels was measured with a Clark oxygen electrode (Orbisphere Material modified). Initially the respiratory rate was determined, for acclimatized fishes, as a function of the decrease in the oxygen concentration of the milieu at diffe­rent temperatures (8°, 10°, 15°, 20° and 25°C) and constant salinity 30 %o . The relationship between metabolism and weight, at these temperatures was then established for two different levels of activity "routine" and "forced". The relationship is described by the equation Q = a Pb (where a and b are calcu­lated constants). The results are comparable with those obtained by KRUGER (1978) using Morone saxatilio W. and WINBERG's (1956) generalized equation for Teleosts. The respiratory response to thermic shock (5°C amplitude) is described.