Abstract
Aquaculture employs a variety of husbandry protocols that need to be evaluated in terms
of health and welfare of fish. Our study demonstrated that monitoring electrical activity from red and white muscles, swimming performances and hormone levels would permit a quantitative measure of fish well-being.
Assessing the well-being of free ranging fish has been fuelled by the need to evaluate anthropogenic stress from the fish perspective. Stressors are directly related to various fish handling procedures. Assessing fish handling protocols or environmental perturbations which affect fish performance, and associated energy expenditures, would permit the development of appropriate mitigative strategies. Aquaculture employs a variety of husbandry protocols that need to be evaluated in terms of health and welfare of fish. Behavioural tests can be used as indicators of short-term stress, but examples are sparse. Measurement of swimming ability, such as critical swimming speed (Ucrit) has been used as indicators of the effects of environmental challenges on the general health of fish (Randall et al., 1987; Brauner et al., 1994) and as welfare indicator for reared sea bass (Carbonara et al., 2006). Frequently, Ucrit has been used as a physiological end point to assess the impact of environmental change (Brauner et al., 1992). There have however been examples where Ucrit is not always a sensitive indicator of metabolic disturbance. Our study expands the use of simple Ucrit measures as an indicator of metabolic disturbance by examining the ability of individual fish to recover from repeated exhaustive exercise events (recovery test). Furthermore, the physiological response to the stress has been evaluated monitoring the contribution of two muscle type (red and white) to the swimming activity and the relative stress hormone levels.