Reviews in Aquaculture, 1–20 doi: 10.1111/raq.12426 Epidemiology of marine gill diseases in Atlantic salmon (Salmo salar) aquaculture: a review Annette S. Boerlage1 , Angela Ashby2 , Ana Herrero2,3 , Aaron Reeves1 , George J. Gunn1 and Hamish D. Rodger4 1 Epidemiology Research Unit, Department of Veterinary and Animal Science, Northern Faculty, Scotland’s Rural College (SRUC), Inverness, UK 2 Fish Vet Group Ltd., Inverness, UK 3 Moredun Research Institute, Pentlands Science Park, Penicuik, UK 4 VAI Consulting, Oranmore, Co. Galway, Ireland Correspondence Abstract Annette S. Boerlage, Epidemiology Research Unit, Department of Veterinary and Animal Gill disease of farmed Atlantic salmon (Salmo salar) in the marine environment Science, Northern Faculty, Scotland’s Rural has emerged as a significant problem for the salmon aquaculture industry. Differ- College (SRUC), An Lochran, 10 Inverness ent types of marine salmon gill disease reported include amoebic gill disease Campus, Inverness, UK. Email: (AGD), parasitic gill disease, viral gill disease, bacterial gill disease, zooplankton
[email protected] (cnidarian nematocyst)-associated gill disease, harmful algal gill disease and chemical/toxin-associated gill disease. The term ‘multifactorial gill disease’ is used Received 29 October 2019; accepted 9 March 2020. when multiple distinguishable types of disease (as opposed to an obvious single primary type) are present. When gill disease is non-specific, it is referred to as ‘complex gill disease’ (CGD) or ‘complex gill disorder’. These two terms are often used interchangeably and are overlapping. The significance of many infectious and non-infectious agents that may be associated with CGD is often unclear. In this review, we summarise aspects of the different types of gill disease that are rel- evant to the epidemiology of gill disease and of CGD in particular.