The development of an artificial hybrid and revealing elements of reproductive isolation between sympatric forms of Dryagin’s char and Salvelinus alpinus complex (Salmonidae) from Sobachye Mountain Lake (Taimyr)

Abstract

The embryonic-larval development (at 3°C) of a hybrid between sympatric lake forms of Arctic char Salvelinus alpinus complex (large females of Dryagin’s char x male goggle-eyed char) from the polar mountain Lake Sobachye (the Norilo-Pyasina water system, Taimyr) was studied. No morphological disturbances were found in the embryonic membrane during development. After hatching, because of yolk sac soaking and blood circulation disturbances along its vessels, about 15% of specimens perished. The most mass disturbances in the development of free embryos and larvae that were manifested in the body curvature, loss of mobility, and subsequent death of a greater proportion of specimens were caused by modifications of differentiation of mesenchymal cells responsible for the axial skeleton formation. It is suggested that anomalies in osteogenesis and a high variation of age when dermal cranial bones (praeoperculum and frontale) appear that bear seismosensory system canal are related to the conflict of genetic programs of the development of parental forms. The rate of embryonic larval development of hybrid specimens exceeds that in the lake small form of Arctic char from Lake Davatchan (Transbaikalia) reared under the same conditions. The reproductive isolation of sympatric Dryagin’s char and goggle-eyed char in Lake Sobachye is provided by both pre- and postcopulation mechanisms. A possible mechanism of formation of reproductive isolation of sympatric forms related to colonization by them of a deep-water biotope is discussed.