The rise of average temperatures in spring and autumn will accelerate the growth rate of rainbow trout, the most important farmed species of fish in Finland. In addition, the length of the effective growing season is also prolonged. These factors will increase the effectiveness and profitability of aquaculture production. On the other hand, when the temperature rises, water oxygen content generally drops while the oxygen consumption of the fish increases. This incurs that the fish cannot be fed efficiently and hence too high water temperature will hinder the growth rate of the fish and cause health problems.
In addition, several parasites and pathogens thrive in warmer water. Because for example fish hatcheries are often located in small inland water bodies with small masses of water, rising temperature might cause problems in particular in juvenile fish production.
Extreme weather events increase production risks in fish farming. For example the increasing frequency and intensity of storms will complicate work especially in open-water cage farming and impact the selection of feeding methods and equipment.
If ice no longer forms due to the warming of the Baltic Sea, the equipment and even the fish can be kept in the sea over winter. Today, sea net cages need to be re-located from open waters to more sheltered areas to protect them against moving ice and super cooled water. If the temperature of the Baltic Sea were to rise so much that the sea would remain free of ice throughout the winters and there would be no super cooling, it would make it easier to practice fish farming in sea areas, because separate winter sites would not be needed.
Significant rise in water temperatures would, however, likely hinder the farming of some cold-water fish such as Arctic char and possibly also European whitefish, but it might improve the farming conditions of for example pikeperch and other percid fish. The effects will depend on where in Finland the fish farms are located and how much the temperatures will rise.
Choosing the right location is key
Luke evaluates the effectiveness of fish farming and the management of production cycles in different sea areas. For now, the best rainbow trout farming conditions are in the water areas in the south of Finland where the water flow rates and depth balance out the effect of high summer temperatures on fish farming. In the future, the optimal farming locations will move to open water areas and fish farming will become more efficient in the north.
Luke participates in the selection of fishery locations as part of Marine spatial planning in Finland.
Luke examines different farmed species and develops fish farming technologies
Luke evaluates how different species of farmed fish, such as European whitefish and pikeperch, will thrive in the changing climate conditions. This guides fish farming industry to target long-term development measures at species with the highest potential to thrive in the future.
Luke estimates what types of farming methods and equipment should be used in the changing farming environments. The equipment especially in sea areas should be proofed to withstand extreme conditions during the farming season. Luke researchers also evaluate the best available feeding methods and their suitability for different farmed species and locations.
Luke develops production processes and materials
Luke examines production cycle of fish farming operations as a whole with the view of ensuring that production is viable and effective from the start to finish under Finland’s conditions. Researchers examine factors such as how recirculating aquaculture and marine aquaculture can be combined and what kinds of solutions will be needed in order to ensure year-round availability of fish for consumers.
Luke maintains selective breeding programmes of farmed fish in order to adapt fish material to the prevailing environmental conditions and to simultaneously improve the international competitiveness of fish farming in Finland. Climate change is a slow process, and selective breeding speeds up the rate of genetic adaptation, making farmed fish better adapted to prevailing environment conditions. Luke examines how effective the current selective programme for farmed rainbow trout is at producing fish material that has adapted to climate change, and provides selective breeding solutions for improving the productivity of fish farming in the changing climate conditions at a global level.