Keanekaragaman dan Distribusi Bivalvia di Estuari Mangrove Belawan Sumatera Utara

Abstract

The research on Diversity and distribution of Bivalvia in Mangrove Estuary Belawan was conducted in May up to June 2013. The method for determining the location of sampling for Bivalves was done using Purposive Random Sampling in 4 (four) observation stations. Sampling was done for 10 replications for each station using a ladle. The results of the laboratory analysis to the physical parameters of water chemistry referred to sea water quality standard for marine life which were set by the Minister of Environment with Decree No. 51 of 2004 The results of research found that Bivalvia consisting of 4 ordo , 5 families , 5 genera and 6 species. Bivalvia density was highest at station 2 at 44.377 ind/m2 and lowest at station 4 at 33.435 ind/m2. Index of Bivalvia diversity was low ( 0.794 to 1, 154 ), whereas, evenness index was classified even for (0.723 to 0.833 ). Similarity index that have high similarity criteria was between stations 1 and 2 (57.143 % ), between station 1 and station 3 ( 66.667 % ) , between stations 3 and 4 (57.143 % ). Criteria of low similarity was found between station 1 and station 4 (28.571 % ), between station 2 and station 3 (28.571 % ) and between station 2 and station 4 ( 50. 00 % ). Subsequently, the index of morista (distribution) of each genus was in cluster. The water temperature, substrate temperature, nitrate, phosphate, organic substrates, the fraction of substrate in the form of sand and clay were positively correlated with the diversity of Bivalvia, while the pH of the water, substrate pH, salinity, DO , BOD . 5 and substrate in the form of dust fractions were negatively correlated.

Penelitian tentang Keanekaragaman dan Distribusi Bivalvia di Estuaria Mangrove Belawan dilakukan pada bulan Mei-Juni 2013. Metoda penentuan lokasi sampling untuk pengambilan sampel bivalvia adalah “Purposive Random Sampling” pada 4 (empat) stasiun pengamatan. Pengambilan sampel dilakukan sebanyak 10 kali ulangan untuk setiap stasiun dengan menggunakan serok. Hasil analisis laboratorim terhadap parameter faktor fisik- kimia air dengan mengacu pada baku mutu air laut untuk biota laut yang ditetapkan oleh Menteri Negara Lingkungan Hidup dengan surat keputusan No 51 tahun 2004. Hasil penelitian ditemukan Bivalvia yang terdiri dari 4 ordo, 5 famili, 5 genus dan 6 spesies. Kepadatan Bivalvia tertinggi terdapat pada stasiun 2 sebesar 44,377 ind/m2 dan terendah pada stasiun 4 sebesar 33,435 ind/m2 . Indeks Keanekaragaman Bivalvia tergolong rendah (0,794-1,154), sedangkan Indeks Kemerataan tergolong merata (0,723-0,833). Indeks Similaritas yang mempunyai kriteria kesamaan tinggi adalah antara stasiun 1 dan 2 (57,143%), antara stasiun 1 dan stasiun 3 (66,667%), antara stasiun 3 dan 4(57,143%). Kriteria kesamaan rendah dijumpai antara stasiun 1 dan stasiun 4 (28,571%), antara stasiun 2 dan stasiun 3 (28,571%) serta antara stasiun 2 dan stasiun 4 (50,00%). Selanjutnya Indeks Morista (distribusi) setiap genus adalah mengelompok.. Suhu air, suhu substrat, nitrat fosfat, organik substrat, fraksi substrat berupa pasir dan liat berkorelasi positif dengan keanekaragaman Bivalvia, sedangkan pH air, pH substrat, salinitas, DO, BOD5 dan fraksi substrat berupa debu berkorelasi negatif