Lake Geneva lavaret

Once native to Lake Geneva, the Lake Geneva lavaret (Coregonus lavaretus) disappeared from the lake in the early 1900s for reasons that remain unknown today. (IUCN 2008) Switzerland’s Office Fédéral de l’Environnement notes that “it is not by chance that vertebrate species in Switzerland facing global extinction comprise an especially large share of lake fish species, as Northern alpine rim lakes harbor several endemic whitefish and char species, each of them occurring in only a few lakes or even just one lake.” (OFE 2016) In its 2016 report Number of Swiss Species in Switzerland Facing Global Extinction, the OFE notes that in the past century, five whitefish species have become extinct in Switzerland, mainly due to water pollution and/or overfishing. The lavaret is the only one of these species to survive in lakes outside of Switzerland. According to the International Union for the Conservation of Nature, it is still found today in the Rhone river basin in France, specifically in Lake Aiguebelette, where its population numbers are unknown, and in Lake Bourget in abundance. Switzerland’s Red List of Threatened Species lists more than 250 species that have disappeared from the country and 554 that are listed as critically endangered; in these two categories combined, water species such as fish and macroalgae make up the highest proportion. (IUCN 2010) The IUCN notes, nevertheless, that “the transition between Extinct in Switzerland and Critically Endangered is often a fluid one.” In fact, because lavaret eggs are cultivated and hatched in Thonon, France, for release in Lake Bourget, the IUCN anticipates that escapes are possible, meaning that the Lake Geneva lavaret population might very well re-establish itself in the future.

Image: Lake Geneva lavaret. Public domain.