Suchergebnisse

Under this backdrop of climate impacts and international and European policy developments, the CERES project (Climate Change and European Aquatic Resources) was funded under the EU Horizon 2020 programme from 2016 to 2020. CERES was designed to advance a cause-and-effect understanding of how climate change will influence European fish and shellfish resources and the economic activities depending on them. More than 150 scientists from 26 partner institutions in 15 countries participated in this four-year project. Partners included national research laboratories, universities as well as industry members from the aquaculture and fisheries sectors and additional stakeholders. Focusing on the most commercially-valuable fish and shellfish, the project increased our knowledge and developed tools needed for adaptation planning for European fisheries and aquaculture sectors in marine and inland waters to anticipated climate change. The project identified not only risks but also opportunities as well as uncertainties of climate change impacts, information needed to enhance the resilience and support the development of sustainable management and governance systems in these Blue Growth sectors. CERES integrated physical, social, ecological and economic analyses relevant to both European fisheries and aquaculture sectors . The program studied the most valuable species and groups and associated businesses across 'Storylines' highlighting sector- and region-specific research findings. CERES developed 24 Storylines to capture the high diversity of European regions (from marine to freshwaters and from high to low latitudes) and commercially important species (from pelagic to demersal fisheries and from the culture of fish (Figure 2). Whereas Storylines form separate, stand-alone products, the present report summarises CERES findings across Storylines to compare and contrast the potential severity of effects of climate change (from risks to potential opportunities) across European marine and freshwaters. This synthesis report includes national-level comparisons of climate vulnerability for both sectors as well as analyses of the potential climate change impacts on the interaction between fisheries and aquaculture.

Background: Gyrodactylus salaris Malmberg, 1957 has had a devastating impact on wild Norwegian stocks of Atlantic salmon Salmo salar L., and it is the only Office International des Epizooties (OIE) listed parasitic pathogen of fish. The UK is presently recognised as G. salaris-free, and management plans for its containment and control are currently based on Scandinavian studies. The current study investigates the susceptibility of British salmonids to G. salaris, and determines whether, given the host isolation since the last glaciation and potential genetic differences, the populations under test would exhibit different levels of susceptibility, as illustrated by the parasite infection trajectory over time, from their Scandinavian counterparts. Methods: Populations of S. salar, brown trout Salmo trutta L., and grayling Thymallus thymallus (L.), raised from wild stock in UK government hatcheries, were flown to Norway and experimentally challenged with a known pathogenic strain of G. salaris. Each fish was lightly anaesthetised and marked with a unique tattoo for individual parasite counting. A single Norwegian population of S. salar from the River Lærdalselva was used as a control. Parasite numbers were assessed every seven days until day 48 and then every 14 days. Results: Gyrodactylus salaris regularly leads to high mortalities on infected juveniles S. salar. The number of G. salaris on British S. salar rose exponentially until the experiment was terminated at 33 days due to fish welfare concerns. The numbers of parasites on S. trutta and T. thymallus increased sharply, reaching a peak of infection on days 12 and 19 post-infection respectively, before declining to a constant low level of infection until the termination of the experiment at 110 days. Conclusions: The ability of S. trutta and T. thymallus to carry an infection for long periods increases the window of exposure for these two hosts and the potential transfer of G. salaris to other susceptible hosts. This study demonstrates that G. salaris can persist on S. trutta for longer periods than previously thought, and that the role that S. trutta could play in disseminating G. salaris needs to be considered carefully and factored into management plans and epidemics across Europe.