Diseases of gadoid fish in cultivation: a review

Given the rapid development of intensive culture systems for cold-water marine gadoids such as cod (Gadus morhua), haddock (Melanogrammus aeglefinus), hake (Merluccius spp.), and ling (Molva molva), an urgent need exists to examine likely threats posed by disease in intensive gadoid culture. While little is known about diseases that may affect or be introduced by cold-water marine gadoid fish once the animals are brought into intensive commercial culture systems, certain risks can be inferred both from an examination of disease problems experienced during the introduction of intensive culture systems for other cold-water marine species and from an examination of the existing literature on gadoid pathogens. This paper provides an overview of the potential disease risks associated with the development of intensive gadoid aquaculture and focuses on previously characterized diseases that the authors consider as posing the greatest threat to intensive gadoid culture. In addition to disease risk, this paper discusses risk reduction, including vaccination strategies and the risk of inter-species infection. Specific viral, bacterial, fungal, protoctistan, and metazoan pathogens are discussed in light of their previous implication in the causation of disease in cultured gadoids or other cold-water species, their occurrence and pathogenicity in wild gadoids, and with respect to life strategies and biology that may favour their propagation within intensive aquaculture systems.