Biological characteristics of atherina boyeri of the Kucchurgan reservoir lake

Aterina boyeri for the first time was recorded the cooling lake Cuciurgan in the 1980s. According to our assumptions, nimerind, together with the water pumped from the Turunchuk arm. Being an invasive species with a short life cycle – aterina boyeri, due to its wide ecological valence and high reproductive potential, it occupied, in a short time, a superdominant position. Currently, it is the most numerous fish species in the lake, whose share during the years 2019-2022 reaches the value of 55,3%. The growth rate and age structure of the local population has halved. Due to the high mineralization and increased thermalization of the reservoir, the aterina boyeri, being a mediterranean, thermophilic species, found a favorable ecological niche here. According to the dominance index, it belongs to the D5 category, according to the constancy index – C3, according to the environmental significance index – to the W5 category. The maximum size and weight of males is 9.4 cm and 3.9 g, and females are 9.8 cm and 4.3 g, which is smaller compared to the marine form. In the period of 2008-2022, there is an exponential increase in the population of the aterina boyeri, which can lead to the exclusion of indigenous fish species.