11: Trout and Char of Northern Europe
Gorm Rasmussen, Jan Henning L’Abée-Lund, Erik Degerman, Janis Birzaks, Piotr Debowski, Evgeny Esin, Johan Hammar, Trygve Hesthagen, Ari Huusko, Martin Kesler, Antanas Kontautas, Grigorii Markevich, Christoph Petereit, Sergey Titov, Teppo Vehanen, and Øystein Aas
This chapter describes native and introduced trout and char species in western Fennoscandia and the Baltic region with a total land area of about 2 million km2. This includes the countries surrounding the brackish Baltic Sea (415,000 km2): the northeastern part of Germany, Poland, Lithuanian, Latvia, Estonia, Russia (Kaliningrad and Saint Petersburg regions), Finland, and Sweden, as well as Denmark, Norway, and the Svalbard archipelago with Jan Mayen and Bear Island in the Atlantic Ocean. The climate in the south is continental while a boreal climate dominates in the mostly Baltic Sea region. In the western part (Denmark, Norway, and western part of Sweden), the climate is influenced by the Atlantic Ocean, and in the mountains of the region, the climate is alpine. The native species are Brown Trout Salmo trutta and Arctic Char Salvelinus alpinus, and the introduced or invasive fish species coming from North America are Brook Trout S. fontinalis, Lake Trout S. namaycush, Rainbow Trout Oncorhynchus mykiss, Cutthroat Trout O. clarkii, kokanee O. nerka, Pink Salmon O. gorbuscha, Chum Salmon O. keta, and Coho Salmon O. kisutch.
The emphasis in this chapter is on the native species, Brown Trout and Arctic Char, and apart from the importance of Rainbow Trout in aquaculture, the rest of the introduced species have insignificant importance in this region.
Brown Trout were among the pioneer fish species colonizing rivers, likely after the last glaciation circa 13,000 years before present. As the ice melted and glacial rebound had not significantly altered watershed elevations, the rivers were accessible for long distances (Huitfeldt-Kaas 1923).