Evalution of habitat suitability index of Alburnoides eichwaldii in Lavij River, Nour, Mazandaran province, Iran.

The presence- absent and frequency of any species in a riverian habitat is hnfluenced by numerous factors, and the particular domains prefer the changes of each habitat factor. The purpose of this study was to investigate the habitat suitability index of Alburnoides eichwaldii in the Lavij River in Mazandaran province. A sampling of fish was carried out at 22 stations in Junuary 2017 by electrofishing, frome the top of the river to the Chamestan city (Kashpel forest park) in downstream of the river. At each station, 11 environmental factors were measured. The results showed that, station 21 is the most suitable station for A. eichwaldii and at this station, parameters such as altitude (until 150 m), width (6-9 m), depth (19-25 cm), substrate (3-7 cm) and water flow velocity (0.6-1 m/s) played the highest role in the high habitat suitability index. According to the obtained chart of the CANOCO software, temperature and ammonium the importance and impact of these variables on the frequency of species, especially A. eichwaldii in the Lavij River. The results showed that areas like station 21, which have been less destroyed in terms of human activities, had the highest level of suitability.