4. Swiss fish – endangered diversity?
Switzerland is a fish paradise. The last ice age created an aquatic landscape in which a unique diversity of fish could develop. Virtually every lake and river is home to rare fishes that only occur locally. But this richness is under threat of extinction: Of more than 130 described fish species in Switzerland, at least 14 have disappeared and around 50% are critically endangered as of 2020. Many species are not well known, and many are yet to be discovered. Scientist and government agencies work together to study and document the unique Swiss fish diversity – one protects what one knows.
4.1 Projet Lac and Progetto Fiumi: a modern inventory of Swiss fish species
Approximately 50% of fish species in Switzerland are endangered. But how many species are there? Where do they live and how can they be protected in the future?
To answer these questions, Eawag, the Swiss water research institute, carried out two research projects – Projet Lac and Progetto Fiumi – between 2010 and 2018. For these projects, scientists systematically collected fish from 31 different lakes as well as many rivers and streams, and compiled the first comprehensive inventory of fish in Switzerland. The around 20,000 fish sampled in these projects now constitute the national reference collection of the museum.
4.2 Reference collection
The museum’s reference collection consists of up to 30 individuals of the same species of fish from every Swiss water body. This number of specimens is necessary to confidently detect genetic and morphological differences between species, many of which occur only locally. A single individual may not be representative of a species.
4.3 Minnow
In 2020, researchers working at the museum conducted genetic analyses that show that in Switzerland there are three species of minnow: the Italian minnow and two species that had previously only been found in southern France and the Danube region. Another surprise came when the researchers were unable to find a trace of the only minnow species supposed to occur in northern Switzerland.
