Pathogens are increasingly reported from populations of aquatic animals. Variations in the frequency and abundance of pathogens depend on spatial or temporal factors as well as those related to host effects such as age or condition. Similarly, the devel-opment of a disease is a function of the combined effects of the pathogen, host and environmental factors. Diseases may be one of several biological and non-biological factors regulating the abundance and composition of stocks or populations of aquatic organisms. Here we review evidence for population effects associated with diseases in wild marine gastropods, bivalves, crustaceans, and fishes. The report provides in-formation on the types of diseases, together with data on diagnostic criteria, causative agents, geographical ranges and effects at the individual and population level. A dis-cussion of the significance of the findings and references to key publications are pro-vided. The overview shows that the effects of diseases may occur at various life stages of affected hosts. The extent to which these effects lead to measurable popula-tion changes (e.g., in growth, reproduction, mortality, recruitment, population de-mography, geographical distribution) is best evident in those populations already subject to long-term population level monitoring, such as in commercial species. However, quantitative evidence of population effects is so far scarce. From the infor-mation available, it may be concluded that some diseases play a much larger role in population performance and dynamics in marine fish and shellfish than previously recognised. Therefore, methods for incorporating disease data into population/stock assessment models should be further explored. In the first instance, this will be rele-vant for commercial species, for which most information is available. However, the development of realistic mathematic models, taking into account population effects of diseases, are becoming also more relevant for non-commercial species, e.g., as part of coastal zone management or assessments of general marine ecology in the context of a more holistic ecosystem approach to marine management.
|Title of host publication||ICES WGPDMO REPORT 2015 : Report of the Working Group on Pathology and Diseases of Marine Organisms (WGPDMO)|
|Place of Publication||Copenhagen V|
|Publisher||International Council for the Exploration of the Sea (ICES)|
|Publication status||Published - 2015|