Evaluating water quality of Nemrut crater lake (Bitlis) and investigating in terms of larvae ontogeny and osmoregulator capacity of Aphanius mento (Heckel, 1843) is distributed within the lake

In this study, it was aimed to determine water quality of the Nemrut Crater Lake in Bitlis province, molecular identification of Aphanius mento, (Heckel, 1843) distributed in the lake, investigate in terms of microscopic and histological development of embryo and larvae, and also evaluate of tolerance to different salinity levels. According to the results of on-site measurements and laboratory analysis of water samples taken dates between September 2018 and October 2019, Nemrut Crater Lake was found suitable for drinking, irrigation, fisheries and agricultural usage. PCR identification performed with the primers specific for Aphanius mento gave a positive results. Fish samples tolerated up to the salinity level of ‰ 22 and the highest value of blood serum osmolarity was determined as 572±7.32 mOsm/Kg. 23.96±1.16 °C, 8.33±0.27 pH, 952±364 µS/cm conductivity and 6.92±0.10 mg/L dissolved oxygen have been identified as spawning conditions. Filamentous and sticky fertilised eggs has a diameter of 1.251±0.316 mm (n:30) with the inclusion of 8-12 oil droplets have started to hatch approximately 11 days after spawning at 23.5 °C. It was determined that newly hatched larvae have a total length of around 3.695±0.225 mm (n:20), have started exogenous feeding at 3 days after hatching (DAH) and started to take particulate baits at the and of 10 DAH.