Chondrostoma spp

Alexander, Timothy & Seehausen, Ole, 2021, Diversity, distribution and community composition of fish in perialpine lakes – “ Projet Lac ” synthesis report, Eawag: Swiss Federal Institute of Aquatic Science and Technology : 122

Chondrostoma spp (nose carp)

Two species are known from the region: Chondrostoma soetta from lakes in the Po catchment and C. nasus from lakes and streams north of the Alps ( Figure 36 ). Unfortunately, both species have declined dramatically in recent years. We observed C. soetta only in Lake Mezzola, and C. nasus only in Lake Sarnen. Both species are likely exterminated in several of the lakes in the Po and Rhine drainage where they were previously recorded respectively. It is possible that Protochondrostoma genei occurs or occurred in some of the lakes in the Po catchment, but we did not record it. However, it is noteworthy here to point out that two distinct lineages of C. nasus occur in the region, the Danubian lineage confined to the Lake Constance catchment and the Atlantic lineage in the rest of the Atlantic drainage of Switzerland ( Figure 37 ) [143].

Figures

Figure 36: Diversity of nose carps (Chondrostoma) in periapline systems.Top left: C. nasus Atlantic lineage (Wiese, Basel). Bottom left: C. nasus Atlantic lineage (Lake Sarnen, Projet Lac).Top right: C. nasus Danubian lineage (Alpine Rhine, Lake Constance inlet). Bottom right: C. soetta (Lake Mezzola, Projet Lac).

Figure 37: Population structure of nase in Switzerland as inferred from microsatellite data. a) Individual population assign- ments estimated by STRUCTURE for K = 2. PCA based on population allele frequencies: b) with all populations included; c) P. toxostoma excluded. Populations Li, Wi, Mu, Bi, Su, Ro, Se and Do are from various Swiss river stations within Thur, Limmat, Reuss, Aare and Rhine downstream of Lake Constance. Ri is the Alpine Rhine, Da an Austrian inlet to Lake Constance, and Na is a Danubian population.The populations in tributaries to Lake Constance (Ri, Da) belong to the Danubian lineage, whereas all other Swiss populations belong to the Rhine lineage (from [143]).