Fish species in Finland

About 100 fish species (98 teleosteans, 1 cartilaginous fish and 3 lampreys) were found to be living in Finnish waters. This publication includes a checklist of Finnish fish species which lists the scientific, Finnish, Swedish and English names in a systematic table, and the occurrence of species in fresh and different brackish water areas in Finland is also recorded. Fifty-eight fish species can be considered to be native and resident. Annually, it is possible to find 67 bony fish and two lamprey species in Finnish waters. There are twenty-two marine fish species. More than one third of the species (24) have fresh and brackish water populations and also anadromous ones. The variable conditions (mainly temperature and salinity) have not made it easy for new species to naturalize into Finnish waters. The fish fauna was basically established about 4 000 years ago when the present Baltic Sea era started. Only four species were added to the species list during the last century but two new species were recognised in 2005. Fourteen new fish species have been imported and introduced into Finnish waters. Four of these species have naturalized, i.e. they have established reproductive and self-sustaining stocks after introductions into some water bodies, and four other species are maintained by repeated introductions, though there has been some reproduction success in a few exceptional cases.

Two lamprey species and 59 fish species are known to reproduce more or less every year in Finnish natural waters. One third of all species are either escapers or have been released from fish farms in neighbouring countries, or explorers that have migrated from the southern Baltic Sea or further away. Three species are extinct and anthropogenic changes affect fish fauna far more than all natural events. Dredging and damming of rivers have had the most significant impact on our fish stocks, mainly on anadromous species. At least 30 or maybe even as many as 47 salmon stocks have been lost and only six native stocks have survived. Similarly, only nine original sea trout stocks out of 62 rivers running from Finland to the Baltic Sea are viable. Acidification and eutrophication have also changed the structure of fish fauna in many water areas. Eleven species or their forms have been put into different classes of conservation depending on their vulnerability. Thirty-one fish species are considered to be commercially exploited. The estimated commercial and recreational fish catch in Finland annually is about 150 million kg. Scenarios on climate change and recent events predict significant changes in the structure of fish assemblages and the arrival of new fish species into Finland, e.g. it may be possible to catch the Chinese sleeper (Perccottus glenii) or some explorer species migrating from the South or East in the near future.