Формы существования предкавказской кумжи - Strutta caucasicus (Дорофеева, 1967) Каспийского бассейна

Abstract

A morphological analysis of brooks trout in Dagestan showed that each spawning herd is morphologically unique and differs from the rest in a certain set of characters. However, all of them, when comparing the age composition, spawning conditions, the extent of spawning migrations in rivers, etc. have a lot in common. All of them meet the definition of a population as a group of individuals united by panmixia, a single territory and isolated to one degree or another from similar groups within the species. The morphological characteristics of trout in the upper of rivers Avar, Andi, and Kara-Koysu further confirms the validity of this approach. Presumably, the structure of trout populations is in continuous change and the differences in morphological indicators are phenotypic in nature and reflect the biotic and abiotic conditions prevailing in this region. The interaction of variability and selection in the population maintains a mobile equilibrium of biological properties forms the passing (brown trout) and residential (trout) forms.
 The trout of Sulakriver breaks up into several local herds (trout of Avar Koysu, Andi Koysu, Kara-Koysu, etc.) with a specific and limited range of its migrations. To a certain extent, differing from neighboring ones, each of the herds maintains its integrity and does not mix with the rest. Thus, the brooks trout of Dagestan seem to combine two functions - the self-reproduction of local settled populations and generating migrant individuals in the Caspian trout (Terek, Samur, Kara-Su rivers, etc.).
 In the rivers of the Kara-Su system, regardless of the place of fishing and the season, trout is represented by almost 100% males. Naturally, the question arises: who ensures the reproduction of trout herds in the absence of females? At the same time, the Salmo truttacis caucasicus (Dorofeyeva, 1967) comes to spawn in these rivers, and its livestock is represented exclusively by females (70-80%). Therefore, brooks trout of the Kara-Su system rivers and the Salmo truttacis caucasicus, coming here to spawn, should be considered as a single reproduction fund. Eggs, laid by either a brown trout female or a trout female, can leave individuals, that roll into the sea and turn into a passing trout, and individuals that remain in the river will be called brooks trout.
 The total reproductive potential of small rivers of the Dagestan coast of the Caspian Sea is currently no less than in native salmon rivers (Terek, Samur). That is why small rivers play an important role in the natural reproduction of trout and brown trout. Among the small salmon rivers of Dagestan, the greatest fishery value have tributaries of the Sulak river, rivers of the Kara-Su system, Shura-ozen, Manas-ozen, etc. Significant differences in the climatic features of these areas inevitably affect the biology of trout inhabiting them.