Analisis Kualitas Air dan Hubungannya dengan Struktur Komunitas Ikan yang Tertangkap di Sungai Naborsahan, Danau Toba Sumatera Utara

Abstract

This research was conducted in Naborsahan River, North Sumatera in April-June 2013. The aim of this research was to observe the water quality in Naborsahan River, fish community structure and the relationship between diversity index and physical and chemical factors of water. The method used in this reasearch is "Purpose Random Sampling. Fishing gear used for fish sampling is stocking net. Data were analyzed descriptively and multiple linear analysis. This research obtained 8 families, 9 genus, 10 species and 10745 individual fish. Highest relative abundance was fish species Bilih of 98.83%, while the lowest was goldfish and Sword Platy fish respectively 0.016%. Diversity index obtained was 0,08 – 0,73, while fish uniformity index is 0.04 - 0.53, dominance index was 0.59 - 0.98 and index of similarity was 50% - 89%. Temperature was 22-25oC, current velocity 0,24-0,44 m/s, depth 0,62-0,79, brightness 0,45-0,76, pH 6,75-7,9, dissolved oxygen 7,1-10,9 mg/l, biochemical oxygen demand 2,22-8,06 mg/l, chemical oxygen demand 5,52-6,672, nitrite 0,003-0,005 mg/l, nitrate 0,424- 0,584, phosphate 0,039-0,059 mg/l and turbidity 4,207-16,617 NTU. Regression results showed that temperature, pH, flow, depth, brightness, DO, BOD5 and COD turbidity are highly correlated with fish diversity. While nitrate, nitrite and phosphate are the lowest correlating factor of diversity of fish.