Larval and fry mortality in intensive cod, Gadus morhua, production: Etiology, pathology, and countermeasures

The project aims at identifying and characterising a condition defined as the bacterial enteritis syndrome of juvenile cod, described from several Norwegian cod hatcheries recent years. The causative agent of the syndrome must be found, and confirmed by t he demands of Koch’s postulate Pathology of cod larvae and juveniles will be studied and characterised by histological and other microscopy techniques. Using immunohistochemistry, and related techniques, it is the aim to describe the pathogenesis of th e condition, including the port of entry and mode of action of the agent(s). The bacterial community of the different compartments of intensive cod production lines will be characterised using modern molecular “fingerprinting techniques” followed by a ta rgeted search by hybridisaton and/or PCR-based techniques for suspected pathogens. As reference material it is the intention to compare materials from several major commercial cod hatcheries with intensive production protocols and one hatchery operating traditional extensive methods. The microbiota and pathology will be compared among the farms, and to controlled challenge experiments. Based on the findings, and following a targeted search for probiotics, prophylactic countermeasures will be suggested and tried in the cod farming facilities. The project involves a long range of partners. In addition to scientific institutions, a range of cod farms are partners, securing samples and utilisation of results. In addition two foreign universities and the N orwegian Veterinary Institute will collaborate. Support letters from the partners will be made available when requested from the project manager.