Welfare & Disease Treatments
Currently, the salmon industry is waging an ongoing war against two parasitic plagues – sea lice and amoebic gill disease (AGD). Traditionally, chemical and medicinal treatments have been used to control outbreaks of these destructive diseases. A growing resistance to available chemotherapeutants for lice control has resulted in the industry adopting non-medicinal alternatives to control this parasite.
This page describes welfare during disease treatments. You can learn about health management and vaccination in the Health section.
Concerns during Disease Treatment
Both chemical / medicinal and mechanical treatments involve similar pre-treatment activity: The fish are crowded and then either treated within the cage or pumped into a well boat or treatment system. This activity is extremely stressful for the animals, as shown by increased avoidance behavior, oxygen consumption and the production of stress hormones including cortisol and catecholamine.
Handling and treatment can also cause physical damage, reducing the fish’s external immune defenses and leaving them vulnerable to infection. The long-term effects of stress include fasting and reduced growth, increased mortalities, and greater susceptibility to disease and reinfection.