According to experts of EFSA’s AHAW Panel the main factors affecting Atlantic salmon welfare are water quality, stocking density, diet and the process by which the fish are sorted by size (grading). The Panel has produced a ranking system for potential welfare hazards in the various farming systems in its risk assessment which can be used by risk managers to gauge the welfare of the different methods. The experts also provide recommendations for future scientific research.
It is said that the interaction is the key elements of the Atlantic salmon farming systems which play a determining role as opposed to any intrinsic differences in the farming methods themselves. Dr. Philippe Vannier, Chair of the AHAW Panel told that this opinion will be followed by other opinions on main fish species: rainbow trout, gilthead sea bream, sea bass, carp, and European eel.
According to the AHAW Panel water quality is an essential for fish welfare and recognised several damaging effects of poor water quality on fish health. IN its presentation the Panel concluded that the introduction of novel, non-marine feed can lead to some problems due to the lack of essential nutrients such as amino acids and polyunsaturated fatty acids, although there is evidence that it could potentially partly replace high quality fish meal.
For Atlantic salmon, a diet containing a high proportion of marine fish meal and oil is important to meet their nutritional requirements. It is also said that grading systems are an important element in husbandry and should be set up to minimise the time fish are out of the tanks or cages, to ensure sufficient water quality is maintained, and to limit stress. Stocking density was also considered to be relevant.
