| Abstrakt: |
The size-age composition, growth, spatial distribution, features of migration, and reproduction of vyrezub Rutilus frisii of the Tsimlyansk Reservoir and the adjacent upstream part of the Don River were studied. Three forms with different types of life strategies are described. Until the 1990s the reservoir was inhabited by the migrant-1 form, characterized by ~300 km long spawning migrations of sexually mature 4–5 years-old individuals into the Don tributary, the Medveditsa River, and following downstream, migration. Since the beginning of the 2000s spawners began to linger in the river, the spawning stock is replenished due to the migration from the reservoir of 4-year-olds maturing the next year (migrant-2 form). The change in life strategy is presumably caused by the lengthening of spawning migrations to 300–700 km. Both forms are characterized by downstream migration in the reservoir. The third, river resident form, long known in the Bystraya Sosna, Krasivaya Mecha rivers, and the adjacent Don area, is characterized by cohabitation in the same locality of all age groups. This form is replenished by migrants from the reservoir, and before the damming of the Don, from the Sea of Azov. Vyrezub inhabiting the Azov-Don region belongs to the migrant-2 form, the spawning grounds of which are located in the downstream reaches of the Seversky Donets River. Since the damming of the Don in the 1950s, in its downstream reaches, on the inter-dam section of the Nikolaevsky and Konstantinovsky hydro systems, a river resident form was formed. [ABSTRACT FROM AUTHOR] |
Full text from SpringerLink