PHYSIOLOGICAL-RESPONSES TO HANDLING IN THE TURBOT

Turbot Scophthalmus maximus were cannulated via the afferent branchial artery and were either net-confined in sea water or in air for 9 min to monitor the stress response of a hatchery-reared marine flatfish. N o mortality was observed. Aerial exposure appeared to mobilize plasma free fatty acids and stimulate the interrenal tissue but had no effect on circulating glucose or lactate levels. This pattern was qualitativ ely similar to that induced by net-confinement in sea water, although the magnitude and duration of the changes were more marked in the turb ot handled in sea water. Aerial exposure had no effect on plasma osmol ality, protein, or Cl- concentrations and only a minor effect on plasm a Na+ concentrations, which was in sharp contrast to the ionoregulator y disturbance noted in turbot which were net-confined in sea water. Ho wever, plasma K+ and cortisol concentrations were similarly elevated b y both handling procedures. The results from these experiments suggest that whilst similarities with the salmonid physiological stress respo nse are apparent, the lack of a plasma glucose response may represent a fundamental difference in turbot stress physiology. (C) 1995 The Fis heries Society of the British Isles