Relationships between Fecundity and the Number of Vertebrae in Common Roach Rutilus rutilus in the Rybinsk Reservoir

Data on the number of vertebrae in spine sections in regard to groups of common roach of different relative fecundity are provided. The average number of abdominal vertebrae turns out to be the lowest in fish with low fecundity. A group of low-fecundity fish is also identified when comparing the average relative fecundity in females with different numbers of vertebrae in the spine. Individuals with 17 abdominal vertebrae have a significantly lower relative fecundity, and those with 16 in the caudal and a total of 40 vertebrae in the spine have a significantly higher fecundity than individuals with a different number of vertebrae in these sections. In females with high fecundity, no differences between fish with different numbers of vertebrae in sections are noted.