Length- Weight Relationship, condition factor, Gastro- Somatic - Index and Stomach content analysis of Schizothorax richordsonii ( Gray 1832) in Setikhola, Parbat, Nepal

Abstract

Schizothorax richardsonii is one of the important major species of an aquatic ecosystem of Setikhola. The main aim of the study is to investigate the length- weight relation, condition factor, gastro-somatic index and Stomach contents analysis of Schizothorax richardsonii. A total of 101 fish individuals were collected seasonally from august 2023 to January 2024 using cast net from Setikhola river. The fishes were measured and weighed using stainless scale and weighing machine respectively before dissecting fish. Qualitative analysis of stomach contents and index of fullness methods were applied for gut content examination. The values of total length and weight varies from 10.3 to 19.6cm and 10.3 to 75.79g respectively. The length-weight relationships of S. richardsonii as calculated on pulled data can be expressed by the equations: W = 0.0059 × TL^3.11 (R 2 = 0.91) for autumn and W=0.024 × TL^2.70 (R 2 = 0.92) for winter. The condition factor ranges from 0.81 to 1.36 during the both seasons indicating fish in good health condition and shows both isometric growth pattern and allometric pattern during both seasons. The mean value of Gastrosomatic index was 11.29 in autumn and 10.21 winter attributed to fish feeding at mdifferent rates. Approximately, 35% of the guts or stomachs were found entirely full followed by moderately full or half-full stomach and only 7% of the stomachs were empty in the winter This fish abundantly feed on green algae most followed by trichopteran and dipteran larvae so consider as omnivore in nature.