Особенности роста различных экологических форм сига Топо-Пяозерского водохранилища (водосбор Белого моря) на современном этапе

Abstract

In northern freshwater ecosystems whitefish is a valuable commercial species. Their decreasing stocks are caused by the human economic activity. Complexity of the ichthyofauna of northern ecosystems is explained not only by the number of species, but also by the abundance of various ecological forms. On the whole, in the Topo-Pyaozero Reservoir, the division of whitefish according to forms was not practiced even in the years of developed fishing with significant catches, and at present most fish producers do not distinguish between these forms. The ratios of different forms of whitefish in catches are relatively stable, but their biological parameters are of interest, if the question arises about the dominance of individual forms of whitefish during the long-term exploitation of their commercial stocks. The aim of the study was to consider the biology of different forms of whitefish in the Topo-Pyaozero Reservoir (the Republic of Karelia). Whitefish is the only limiting object of fishing in the Reservoir. By morphological and ecological features there are distinguished 6 forms of whitefish: 2 lacustrine (at least 50% of the catch) - coastal and deep-water (lattaneni), and 4 anadromous (leaf fall (lehtisiiga), kukkaneni, kutcheri, suurisiga). All forms can be found on both the Pyaozero and Topozero reaches of the Reservoir. In the light of the materials given on the features of all forms of whitefish caught in the Topo-Pyaozero Reservoir, it is clear that a biologically justified catch size will correspond to a minimum size of whitefish - 26 cm. These data will encourage more abundant catches of whitefish, which corresponds to the current Fishing Rules for Northern reservoirs of Russia