On the hydrofauna of the first Batabat water reservoir

For the first time generalized data on hydrofauna of the First Batabat reservoir are given. In the fauna 6 species of zooplanktonic organisms are revealed, with absolute predominance of large predatory copepod Hemidiaptomus rylovi Charin, 1928. The mean body length of fertilized egg-bearing female crustaceans was 3.6 mm to the furca and 5.1 mm to the tip of the telson. In the ecosystem, Daphnia pulex Leydig, 1860 typically produces its last parthenogenetic generation in September. In the macrozoobenthos of the reservoir, 40 species of macrobenthic organisms were found, with the Heteroptera (9 species) and the Chironomidae family (9 species) predominating in terms of the number of species. According to all its ecological indicators Gammarus lacustris (Sars, 1863) is the dominant bottom organism of the ecosystem. The maximum number of population individuals - 346 spec./m2 and biomass - 2804 g/m2 was calculated in the last decade of June 2017. Being a detritophage with a wide food spectrum, individuals of the higher crayfish have an abundant food base in the reservoir. The first Batabat reservoir located in the high mountainous region of the autonomous republic and having favorable natural and geographical conditions is characterized by high biological productivity.