Working Group on Pathology and Diseases of Marine Organisms (WGPDMO)

Abstract

The ICES Working Group on Pathology and Disease of Marine Organisms (WGPDMO) agenda included several topics related to diseases and pathology in wild and farmed fish and shellfish. The group produced a report on new disease trends in wild and farmed fish and shellfish in the ICES area based on national reports from fifteen member countries. Notable reports for wild fish included a decreased prevalence of M74/thiamine deficiency in eggs from salmon hatcheries in Sweden, a continued increase in hyperpigmentation in dab in North Sea areas of the United Kingdom, and the observation that piscine orthoreovirus subtype 3 (PRV-3) has now been recorded in wild salmonids from both freshwater and marine environments in northern Europe. Reports for farmed fish included the first confirmed clinical field case of salmonid alphavirus (SAV-1 genotype) with pathology consistent with pancreas disease in freshwater Atlantic salmon in Scotland, the first case of furunculosis in Canada associated with Aeromonas bestiarum, reported in farmed Atlantic salmon in British Columbia, and the detection of Cyclopterus lumpus virus (CLuV) in numerous disease outbreaks in cleaner lumpfish in Norway. The health of lumpfish and other cleaner fish used in salmonid aquaculture and the broader biosecurity and ecological implications of cleaner fish use are intensifying concerns that will be the focus of a new Term of Reference added for Years 2 and 3 of the present cycle. Notable reports for shellfish included the first observation of an OsHV-1 microvariant in the USA and in the Western Hemisphere more generally, in aquacultured Pacific oysters in California; the detection of OsHV-1 μVar in association with high mortality in a new area in Ireland; the first detection of Marteilia cochillia in cockles in the United Kingdom, in a Wales estuary; and the first detection of Marteilia refringens on the island of Ireland, in blue mussels in Northern Ireland. Work on additional documents included syntheses on the role of Vibrio pathogens contributing to mortalities in shellfish aquaculture as well as seafood-associated disease risks in humans, on the contemporary status of oyster pathogen Bonamia ostreae, on complex gill disease in salmon, and on emerging health issues affecting wild salmonids of the Baltic region. The present status of the Fish Disease Index and plans for its continued development were also discussed, as were plans for the Workshop on Emerging Mollusc Pathogens (WKEMOP) scheduled in June 2019. Two new ICES Identification Leaflets for Diseases and Parasites of Fish and Shellfish were pub-lished, and five new leaflets are planned for completion in 2019.