Comparison of biometric characters between Rutilus pigus (La Cepede, 1803) and Rutilus virgo (Heckel, 1852)

The study concerns biometric characters of two species of the genus Rutilus Linnaeus 1758, i.e. Rutilus pigus (La Cep&egrave ; de, 1803) from the Adriatic and Rutilus virgo (Heckel 1852) from the Danube River Basin. Rutilus virgo (the Danube roach) inhabits all larger rivers of the Danube River basin (the Rivers Sava, Drava, and Mura) and their larger tributaries in Slovenia. R. pigus (Italian roach, Pigo) inhabits large northern Italian rivers and some lakes. Their distribution areas are completely separated. Both are important and frequent sport fishing species. Despite this, their ecology and biology are nearly unknown. The intent of the study was to compare the biometric characters of both species. A total of 31 specimens from the River Kolpa (the Danube basin) and 27 specimens from the River Monticano (the Adriatic basin) were morphologically and meristically studied. Twenty-four morphometric and six meristic characters were analyzed using standard numerical taxonomic techniques.