Struktur Komunitas Ikan pada Bagian Tengah Sungai Barumun, Sumatera Utara

Abstract

The Barumun River is a river located in the northern region of Sumatra Island, characterized by a tropical rainforest climate and a diverse variety of nekton species. The river is utilized by the surrounding community, primarily as a fishing ground for local fishermen. Increasing human activities have led to changes in land use and increasingly diverse lifestyles. The uncontrolled disposal of waste from development activities along the river has resulted in water quality degradation, surpassing the river's carrying capacity. This study was conducted in October 2024, with fish sampling carried out over a one-month period in North Sumatra Province. The community structure of fish in the midstream section of the Barumun River showed a diversity index (H') ranging from 1.64 to 2.22, categorized as moderate. The evenness index (E) values ranged from 0.71 to 0.96, indicating high evenness across all research stations. The dominance index (C) values ranged from 0.13 to 0.33, categorized as low. The relative abundance (RA) of nekton in the midstream Barumun River revealed the highest abundance from the Cyprinidae family, specifically Rasbora dusonensis (yellowtail silverside) with an RA value of 54% and an FI value of 100% at station 11, and Barbodes schwanenfeldii (lemeduk fish) with an RA value of 19% and an FI value of 100% at station 15. The relationship between water quality and fish abundance and diversity in the midstream Barumun River, North Sumatra Province, showed a positive correlation with depth, pH, current, TDS, DO, TSS, and turbidity. In contrast, clarity and temperature exhibited a negative correlation.