The morphological characteristic and feature of nutrition of Amur sleeper (Perccottus glenii Dybowski, 1877) on the new part of range (the Komi Republic territory)

Amur sleeper (Perccottus glenii Dybowski, 1877) is invasive species of fish for the territory of Russia and different European countries. That article is devoted to small population of Amur sleeper in Komi Republic, which a recently appeared in that territory. The study was intended to establishing the morphological and biological features associated with the formation of population of the new area and the possibility of its further settlement in Vychegda River. The analysis of different counting signs showed a high levels of variability and the presence of anomalies in the development of the vertebral column (20-57% of defective individual in the samples). The formation of a new population occurred on the basis of a limited and random set of individuals genotypes (the founder effect). A hypothesis what this was the reason for the high level of variability of morphological signs and their developmental anomalies is proposed. The characteristic of nutrition carried out by the “index of relative significance” indicates that the main part (55-92%) of their diet ration was benthic organisms. Biologically significant overlapping of the food niches produced by the Horn index is detected for Amur sleeper and ruff (Gymnocephalus cernuus (Linnaeus, 1758)). Significant tolerance level to environmental factors and short life cycle will yield to increase of density and further expansion of range square in Vychegda river basin. The middle flow of Vychegda river is characterized by a high degree of lakes abundance (15 ha of lakes to 1 km of river flow), that will be a favorable factor for occupancy of this species at the “lake” stage of invasion. A floodplain lakes which perform of the refugium functions will increase a density of Amur sleeper population in the introduction area. Eventually, this will lead to start of a “river” vector of the invasive process, and gradual migration in the main channel and the subordinate system of the Vychegda and Northern Dvina rivers. For aquatic ecosystems of European North-East of Russia Amur sleeper will represent an ecological hazard by eating of part of the juvenile stage individuals of aboriginal fish species and competing for the food resources.