Gobio 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 : 117-118

Gobio spp (gudgeon)

Prior to Projet Lac, only one species of gudgeon, Gobio gobio was known to occur in Switzerland. Gobio gobio is native to much of Europe north of the Alps and was recorded by Projet Lac in most lakes in the Rhine catchment (not recorded in Brienz and Lower Constance and naturally absent from Rousses, Joux and Brenet), as well as Annecy, Bourget and Bret in the Rhone catchment. Although the endangered Romanogobio benacensis is the native gudgeon in the Adriatic drainage, and its geographic distribution in Italy touches the borders to Switzerland [140, 141], it has not yet been recorded in Switzerland. And even though G. gobio is known to be invasive in much of the Italian Po drainage, no Gobio were recorded by Projet Lac in the lakes south of the Alps.

In Upper Lake Constance, genetic barcoding of ten Gobio caught in Projet Lac, revealed five specimens of the blunt-snout gudgeon, Gobio obtusirostris and five Gobio gobio . The former species is native to the Danube river catchment and had not been previously recorded in Lake Constance nor in Switzerland. External phenotypic differences between the G. gobio and G. obtusirostris caught in Lake Constance were small ( Figure 31 ). All Gobio in caught in Lake Constance were from fishing actions in the southern corner of the lake between Romanshorn and the mouth of the Rheintaler Binnenkanal. Individuals of both G. gobio and G. obtusirostris (according to barcoding) were caught together in two fishing actions. One individual of G. obtusirostris was also caught by Progetto Fiumi in the nearby Salmsacher Aach, which enters Lake Constance near Romanshorn.The present-day Alpine Rhine originally flowed into the Danube River (until the end of the last ice-age) and Lake Constance is known as a natural contact zone between Danubian and Rhine lineages of several other fish genera ( Barbatula [142], Chondrostoma [143], Lota ). Projet Lac provided the first such evidence for the two Gobio species [9].

Figures

Figure 31: Four adult Gobio caught in Upper Lake Constance in the same electrofishing action near the mouth of the Rhein- taler Binnenkanal. Genetic barcoding revealed that two individuals had the mitochondrial DNA of Gobio gobio (upper) and two of Gobio obtusirostris (lower.