Fish Biodiversity in TheMiddle Streamof BilahRiver, Labuhanbatu Regency, Indonesia

Abstract

The purpose of this research is to know the quality of Bilah River which review from biodiversity of gastropods. This research conductedfrom March-May in 2020. This research uses Explorative Deskrptif method. Selection of research stations based on government administration or sub-district consisting of Pangkatan subdistrict, Rantau Selatan district and Bilah Barat district. Handsorting gastropod sampling. In data analysis is done calculation of diversity index(H'), evenness index (J'), the similarity Index (IS). The gastropods species were found on Bilah river 9 species: Anantome helena, Bellamya sp., Cerithidea cingulata, Melonoides torulosa, Melanoides tuberculata, Nassarius coronatus, Pomacea sp., Sulcospira testudinaria andThiara scabra. The highest diversity index (H') on station 9 (1.46) and the lowest station 4 (1.01) by medium category. The highest evenness index value on stations 9 (0.70) and lows at Station 4 (0.56) with medium population Evenness index(J') category. The highest Similaritas (IS) index on stations 3, 4, 5 and 7 (100%).