A paradoxical bias in knowledge about Norwegian freshwater fishes: Research efforts during 1980–2020

Norwegian freshwater systems are in general species-poor. That is particularly the case for freshwater fishes. Only 32 species are considered native, whereas an additional 12 species are non-native. Some of the non-native species are also considered to be invasive and have negative ecosystem effects. Freshwater fishes are exposed to numerous stressors throughout their life cycle, many of which are of anthropogenic origin. In order to manage and conserve the diversity of fish there is a need for basic knowledge and understanding. Here I make an effort to review the published research on all Norwegian freshwater fish species during the 1980–2020 period, based on a standardized search on the Web of Science. Over 2000 relevant articles were retrieved and evaluated following the search. The research activity has been highly biased, with most research activity directed at a few species of high economic and societal value. Most work was directed at Atlantic salmon Salmo salar and brown trout S. trutta, and in general towards species within the salmonid family. Extremely little attention was directed at species such as the lampreys (four species) and sculpins (three species). Also, many species that have been listed on the Norwegian Red List during various time periods have not been given any particular attention. This lack of attention was also evident for most of the non-native species. The strong bias in research activity and lack of attention given to many species will clearly lead to difficulties in making appropriate management decisions. This is unfortunate, in particular at a time when climate change may lead to numerous ecosystem-level changes.