Catalogue of morphological scale deformities from 13 species of freshwater fish from the Kaniv Reservoir (Dnieper), Ukraine

Among the morphological anomalies that have been reported in fish so far, abnormalities in scale shape and structure have been described from a limited number of species worldwide. The aim of the present study was to extend this knowledge by identifying and describing such scale abnormalities in freshwater fish from the Kaniv Reservoir, Ukraine. Scale deformities were common in most of the species investigated (Cyprinidae, 10 spp.; Percidae, 2 spp.; Esocidae, 1 sp.), with some differences in the number of cases among them. A wide variety of scale deformities was found, classified into two major categories, slight and severe. In all, 211 abnormal scales (172 slight and 39 severe deformities) were observed and described. The scale deformities described herein could help direct future work on the relationships between the condition of the environment and fish health.