Aquaculture in Lake Storsjön: an ecosystem services based investigation

Abstract: The purpose of this thesis is to investigate if the application of the ecosystem services concept can provide decision makers and stakeholders with additional relevant information for decisions regarding establishing of aquaculture on a local level, using the Lake Storsjön as a case study. In order to provide this knowledge, three different tasks are carried out within this thesis: the identification of the main ecosystem services provided by Lake Storsjön, the understanding of ecosystem services that will be affected by the expansion of aquaculture and the identification of the services that will be used for a possible expansion of the aquaculture sector. The CICES methodology (Common International Classification of Ecosystem Services) is used to identify the ecosystem services provided by Lake Storsjön. The understanding of the affected ecosystem services is carried out with the use of a Delphi-inspired approach. The identification of the services required for the establishment of aquaculture is driven by a cross-reference matrix. Lake Storsjön provides thirty-nine out of the fifty-nine ecosystem services included in the CICES. About half of these will be effected by environmental impacts connected to operations of ecosystem management required by aquaculture expansion, mostly with a low or medium degree of impact. An increase in the implementation of aquaculture might cause detrimental trade-offs with these ecosystem services: “Wild animals”, “Genetic materials from all biota“, “Disease control”, “Maintaining nursery populations and habitats” and “Filtration/dilution/sequestration/storage/accumulation by ecosystem”. An expansion of the aquaculture sector requires seven of the ecosystem services provided by Lake Storsjön. The vital services for this process are: “Surface water for non-drinking purposes”, “Filtration/dilution/sequestration/storage/accumulation by ecosystem” and “Chemical condition of freshwater”. These services have to be safeguarded and maintained in order to guarantee adequate conditions for an expansion of this sector. At the same time the expansion of aquaculture supports the service “Animals from in situ aquaculture”. The benefits connected to the implementation of aquaculture shall be economically assessed and compared to the actual economic value delivered by the other ecosystem services in order to further understand the positives and negatives outcomes of aquaculture expansion in an ecosystem services perspective. This is considered to be a relevant step for strategic and decision making processes concerning aquaculture expansion in Lake Storsjön. In addition to the economic perspective, it seems that the most relevant factor when discussing planning and development processes towards ecosystem services is the importance of not overshooting the resilience ability of the ecosystem in order to ensure the accessibility of the services to future generations. This belief is recommended to be applied to Lake Storsjön in order to guarantee a conscious expansion of the aquaculture sector on a social, economic and environmental level.