Hubungan Kualitas Air dengan Struktur Komunitas Ikan di Sungai Buaya Kabupaten Sergai dan Kabupaten Deli Serdang Provinsi Sumatera Utara

Abstract

The relationship between of water quality with structure of fish community in Buaya river, Sergai and Deli Serdang regency of North Sumatera was conducted on April to June 2013. The determination of sample location point is using “Purposive Random Sampling”. Fishes samples were taken by net and identified in the Laboratory of Natural and Environmental Resources Management, Mathematics and Nature Science Faculty of North Sumatera University. The result showed that fishes had been found 3 ordo, 5 family and 7 species. The highest density, relative density and presence frequency of fishes from species Mystacoleucus marginatus in 1st station. Species Hampala macrolepidota in 2nd station, and Oreochromis niloticus in 3rd station. The diversity index of fishes in the three research stations are about 1,171-1,532 with abundance index 1,023- 1,184 and dominant index about 0,235-0,351. The highest similarity index are between 1st and 2nd stations with grade 88,88%. The sex ratio of fish is different and the growth pola are negative allometric. The result of Storet method for water quality parameters of Buaya river that measured are DO, pH, temperature, light intensity, flow rapidity, BOD, penetration, oxygen saturation, nitrat, and posphat showed the water quality still very good. The result of Pearson correlation test showed that nitrat positive correlated with real effect towards diversity of fishes in Buaya river.