The impact of environmental parameters on fish biodiversity of Lavij River, Noor, Mazandaran Province

In order to study fish biodiversity status in Lavij River and its relationship with environmental parameters, in January 2017, sampling was carried out in the river (about 20 km of river length) by electrofishing. 6 species of fish, including Luciobarbus capito، Paracobitis sp. , Ponticola cyrius، Capoeta capoeta، Alburnoides eichwaldii and Squalius cephalus were identified. In the first and second stations, because of high altitude, and in stations of 13, 16 and 17 due to human manipulation, no fish sample was collected, while most samples were collected at stations 21 and 22. Biological indices showed the greatest value of Shannon Index in station 22 (H’=1. 34) and the lowest value was obtained in stations 3, 4 and 5 (H’=0) with the only recorded species, Luciobarbus capito. Station 3, 4 and 5 had the highest Simpson’s dominance index. Regarding the abundance of species and specimens caught at stations, the highest species richness was detected at station 10. Spearman correlation between abundance and diversity indices with environmental parameters indicated that Shannon index had a significant correlation with nitrate, ammonium and Ec (p<0. 05). Based on the results of RDA, changes in environmental parameters can affect the abundance of different species, as the abundance of Alburnoides eichwaldii is mostly influenced by changes in temperature and ammonium level. Indices of Shannon, Pielou and, to some extent, Margalef revealed high changes in Lavij River and directly correlated with nitrate and ammonium levels. According to the sectional study, the present work probably introduces some information on the status of fishes in Lavij River, but not as much as completely. However, this can provide an overall view of fish’s status in river to the ecologists