Diversity, distribution and community composition of fish in perialpine lakes – “ Projet Lac ” synthesis report Author Alexander, Timothy Author Seehausen, Ole Eawag: Das Wasserforschungsinstitut des ETH-Bereichs Überlandstrasse 133, CH- 8600 Dübendorf text 2021 2021-11-12 Eawag: Swiss Federal Institute of Aquatic Science and Technology https://www.dora.lib4ri.ch/eawag/islandora/object/eawag:24051 book http://doi.org/10.5281/zenodo.5779569 723c8018-f87a-440a-bed1-3d2fe2a46e42 978-3-906484-76-1 5779569 The Phoxinus of Lake Chalain in the Jura region of the Rhone drainage, as well as those from tributaries of the Doubs (sampled in Progetto Fiumi), were revealed to be P. septimaniae . This is consistent with the known range of this taxon that was recently extended from the Pyrennees to the Jura Rhone [147] . More surprisingly, Progetto Fiumi data revealed that P. septimaniae , nearly completely absent from the lakes in the region, does occur in most streams of northern Switzerland, often together with P. csikii .The exception is the Alpine Rhine (and Lake Constance) where the species seems absent. Interestingly, of all our northern Swiss lake samples, only one individual from Lake Thun was barcoded as P. septimaniae whereas 45 were P. csikii . This is in contrast to Lake Chalain in the Rhone drainage, where P. septimaniae lives in the lake in the absence of P. csikii , and also in contrast to the two alpine lakes, Sils and Poschiavo, where both species co-occur.