Derjugin’s Mountain Newt (Neurergus derjugini derjugini) inhabits the Zagros Mountains in northeastern Iraq and western Iran. The present study was conducted in Rikhalan village (Mirisour stream) in Marivan County, western Kurdistan Province, to determine habitat requirements and population size of Derjugin’s Mountain Newt. From April through May 2020, the capture-mark-release-recapture technique was used to estimate population size. Habitat parameters including pH, dissolved oxygen and electrical conductivity of water, water and air temperature, the size of bedrocks, water flow speed, and canopy and aquatic vegetation cover were measured. A total of 3175 specimens of Derjugin’s Mountain Newt (1853 males, 1322 females) were captured and recaptured. Population size was estimated using the software CAPTURE and the Jolley-Seber method. According to the results obtained by means of the MARK and Ecological Methodology software, the population size of Derjugin’s Mountain Newt in the study area was between 2401 and 2554/1664 m², 1165 and 2877/1664 m², respectively. Habitat preferences of Derjugin’s Mountain Newt in the Mirisour Stream are clear shallow water with a slow flow speed, pH 8.23–8.36, electrical conductivity 292–331 µS/cm, dissolved oxygen 7.26–8.42 mg/l, water temperature 12–17.5°C, and vegetation to include oak (Quercus brantii, Q. infectoria), plane (Platanus orientalis), walnut (Juglans regia), and willow (Salix spp.) while the aquatic vegetation consists of broadleaf (Mentha sp.) and orchard grass (Dactylis glomerata). Presence and abundance of this species were considerably higher at greater altitudes. The key threat to the species is habitat loss, which is caused by water being siphoned off for agricultural purposes and blocking springs as a result
