Interannual Variability of Morphological Characters in Roach Rutilus rutilus (Cyprinidae) Underyealings of Coastal Habitats in of the Rybinsk Reservoir off Borok Settlement (Yaroslavl Oblast)

Interannual variability in the underyearlings of roach Rutils rutilus , sampled in different years at the same point of the Rybinsk Reservoir was revealed. The variability is manifested in the number of vertebrae and soft rays in the fins, as well as in the frequency of vertebral phenotypes and pharyngeal tooth formulas. Within one year, groupings of underyearlings of different sizes do not differ in meristic and qualitative characteristics. The number of spinal anomalies in roach underyearlings is low; a negative correlation was revealed between the average number of vertebrae and the proportion of fish with anomalies in the samples of different years.