“…In teleosts, cortisol is a major stress hormone and its plasma level increases are positively correlated with stress levels (Billard and Gillet, 1981;Pickering et al, 1982;Sumpter et al, 1986). Many studies of adult salmon also reported a correlation between plasma cortisol concentration and stress (Billard and Gillet, 1981;Pickering et al, 1982, Barry et al, 1995Pickering and Pottinger, 1987a,b;Carragher et al, 1989;Carragher and Sumpter, 1990;Foo and Lam, 1993;Chopin et al, 1996;Jardine et al, 1996;Waring, et al, 1997, Carruth et al, 2000. Acute handling and confinement (stressors) of juvenile and immature Atlantic salmon for 3 hours is accompanied by an increase concentration of plasma cortisol (Carey and McCormick, 1998).…”