Fish community structure along altitudinal gradients with relation to environmental variables in Ratuwa River of Eastern, Nepal

Studies on fish community structure along altitudinal gradients of rivers are lacking in Nepal. This study was carried out to gauge the diversity and composition elevational gradient Ratuwa River. The varies between 70 m 1300 m. Fish samples were collected based habitat representativeness from April (spring) 10-18, July (summer) October (autumn) 2020 January (winter) 2021. A total 3447 specimens representing 4 orders, 14 families 36 species identified. Both abundance studied ichthyofauna vary with gradient. present affirmed that Opsarius bendelisis, Schistura multifasciatus, Garra annandalei, Brachydanio rerio, Aspidoparia morar, scaturigina major contributory (>1%) for both space time spectrums. testing showed significant difference spatial spectrum (R=0.72, P<0.01) but no temporal variation (R=-0.034, P>0.05). results hinted assemblage varied significantly low high elevations, altitude, water temperature, velocity, dissolved oxygen pH found as influential factors (P<0.05) distribution.