HIDDEN 01

HIDDEN is a joint project run together with Swedish (Lst Västerbotten, Lst Norrbotten, Sveriges geologiska undersökning - SGU) and Finnish (POP-ELY, GTK) collaborators. The project focuses on the state of river estuaries in Swedish and Finnish coats of the Kvarken and the Bothnian Bay regions. Luke's work package includes: (1) investigation of suitable conditions and areas for the development of European whitefish eggs in relation to various types of river estuaries, and (2) mapping of northern pike breeding areas in river estuaries and their surrounding areas. The incubation experiment of whitefish eggs will identify the conditions for the fish reproduction in relation to environmental factors relevant for estuaries, such as exposure, eutrophication level and land use. In addition, the data on the pike larvae will be combined with data previously collected by Luke, with the combined knowledge then being used for modelling pike breeding areas in the Gulf of Bothnia. Luke's previous breeding area modelling has been widely used in decision-making processes. However, the relevant breeding area data for coastal fish, and the pike in particular, are quite old and mostly missing from the northern parts of the Gulf of Bothnia. The work will therefore address obvious knowledge gaps. Both of these fish subprojects are linked to other investigations of the effects of eutrophication and climate change on the coasts of the northern Baltic Sea. The data produced in the other work packages of the project will be used in the context of Luke's work package.

Together, the different sections will provide background information for decision-making measures, fisheries management and environmental impact assessments. The work is also related to other ongoing Luke projects (e.g. NiittyHOI, Biodivesea) and it will deepen cooperation between the participating parties.