Fish farming is comparable to livestock production. By definition, fish is an animal and is thus protected under the Animal Welfare Act. To ensure good fish welfare, employees on fish farms and in slaughterhouses must have the competencies needed and must have passed a specialist fish welfare course examination approved by the authorities.
Regulated by law
Fish health and welfare in fish farming depends on good management practice, and this is regulated under applicable aquaculture legislation. Good management practice requires species-specific knowledge of nutritional requirements, natural behaviour and preferred water quality. In addition, good hygienic conditions are important to keep the fish healthy.
Certain external markers on the fish serve as indicators of reduced welfare, such as fin and skin erosions, bum eye disease and mortality. Possible causes for such markers are aggression due to lack of feed, too high fish densities or suboptimal water quality.
Knowledge to ensure fish welfare
It is generally difficult to visually observe the well-being of fish. However, through behavioural studies of fish and their normal swimming activity, we can gain an impression of their feeling of comfort. It is also possible to measure stress markers in fish and thereby gain information about their level of stress as well as their capability to handle it. Individual fish that cannot handle a stressed situation will experience reduced welfare and become more susceptible to diseases. When stress markers are measured under different environmental conditions (water quality, water flow, temperature), the results can give indications about the preferences of the fish. This knowledge of preferred environmental conditions can be used to ensure good fish welfare on a day-to-day basis at fish farms.