This study investigated the eect of ®ve sampling procedures on serum cortisol, glucose, total protein, osmolality, Na + , Cl ± , K + and Ca ++ concentrations in 2-year-old cultured sea bass (Dicentrarchus labrax L).Mild disturbance caused by rapid removal of ®sh and brief handling did not induce signi®cant variation in any of the blood parameters investigated. Con®nement and crowding elicited a high and signi®cant increase in serum cortisol, glucose, osmolality, Na + , Cl ± , and Ca ++ concentrations. Exposure to MS 222 (140 mg L ±1 ) signi®cantly increased osmolality, but not ionic concentration. Site of blood withdrawal (cardiac sinuses/caudal vein) had no eect on the concentration of analysed blood constituents, except for K + levels. Scattered literature of sea bass blood chemistry is reviewed and compared with`normal' ranges of blood constituents measured in this study. We conclude that it is necessary to select and rigorously execute an opportune blood sampling procedure whenever blood constituents are used as indicators of ®sh functional state.

This study investigated the eect of ®ve sampling procedures on serum cortisol, glucose, total protein, osmolality, Na + , Cl ± , K + and Ca ++ concentrations in 2-year-old cultured sea bass (Dicentrarchus labrax L).Mild disturbance caused by rapid removal of ®sh and brief handling did not induce signi®cant variation in any of the blood parameters investigated. Con®nement and crowding elicited a high and signi®cant increase in serum cortisol, glucose, osmolality, Na + , Cl ± , and Ca ++ concentrations. Exposure to MS 222 (140 mg L ±1 ) signi®cantly increased osmolality, but not ionic concentration. Site of blood withdrawal (cardiac sinuses/caudal vein) had no eect on the concentration of analysed blood constituents, except for K + levels. Scattered literature of sea bass blood chemistry is reviewed and compared with`normal' ranges of blood constituents measured in this study. We conclude that it is necessary to select and rigorously execute an opportune blood sampling procedure whenever blood constituents are used as indicators of ®sh functional state.