Length–weight Relationship of Six Cyprinid Fish in the River Vardar (republic of Macedonia)

This paper considers the length–weight relationship of six out of eight most commonly found fish species inhabiting the Vardar River biotope, the largest riverine system in the central part of the Balkan Peninsula: Alburnoides bipunctatus (Bloch, 1782); Alburnus alburnus (Linnaeus, 1758), Barbus macedonicus Karaman, 1928; Barbus peloponnesius Valenciennes, 1842; Chondrostoma vardarense Karaman, 1928 and Leuciscus cephalus (Linnaeus, 1758), two of which are endemic. Satisfactory results for all the length groups have been determined only for B. peloponnesius whereas for the other fish species exceptions were noted for some of the length classes. The rational behind this can be sought in two reasons: insufficient number of individuals in a concrete length class or sexual maturation causing the prespawning or postspawning influence on the change of the weight of the fish.