Studi Struktur dan Pertumbuhan Populasi Kerang Pokea (Batissa violacea var. celebensis, von Martens 1897) di Sungai Pohara Sulawesi Tenggara

ABSTRAKPokea merupakan bivalvia air tawar yang hidup di segmen muara. Bivalvia ini terusmengalami tekanan sejalan dengan peningkatan aktivitas kegiatan penangkapan danmenurunnya kualitas perairan. Penelitian ini bertujuan untuk mengetahui struktur danpertumbuhan populasi kerang pokea di Sungai Pohara Sulawesi Tenggara. Penelitian inidilaksanakan di segmen muara Sungai Pohara selama setahun dari bulan Maret 2007-Februari2008. Parameter populasi (L∞ dan K) dan to masing-masing dianalisis dengan menggunakanpergerakan modus frekuensi panjang dan nilai L0=0.025. Pola pertumbuhan dianalisismenggunakan inverse von Bertalanffy sedangkan struktur populasi dianalisis menggunakandistribusi normal dari plot Bhattacharya yang secara keseluruhan terakomodasi pada programFiSAT II versi 3.0. Hasil penelitian menunjukkan bahwa lebar asimtotik dan koefisienpertumbuhan jantan dan betina masing-masing yaitu 7.16 cm, 0.59 dan 6.92 cm, 0.96. Olehkarenai tu, pertumbuhan pokea betina lebih cepat dibandingkan pokea jantan. Populasikerang pokea tersebar pada berbagai kelompok ukuran yang mewakili ukuran muda, dewasadan tua dengan nilai tengah berada pada 1.49 dan 6.01 yang menyebar pada tiga kelompokukuran. Kelompok ukuran dominan pada jantan betina relatif berbeda yang tersebar padanilai tengah masing-masing 1cm dan 2cm. Secara umum, struktur populasi pokea di SungaiPohara relatif stabil.Kata kunci : pokea, pertumbuhan, struktur, populasi, sungai, PoharaABSTRACTPokea clam was fresh water bivalve that lived on well into estuary segments. Thisbivalve have experienced in under pressure as activity increase in fishing events and decreasein water quality. This research aimed to understand the structure and growth population ofpokea clam in Pohara river on Southeast Sulawesi. This research was conducted in estuarysegment of Pohara river from March 2007 to February 2008. Parameters of population (L∞dan K) and to were analyzed by using movements in modus of length frequency andLo=0.025. Growth pattern was analyzed by using von Bertalanffy inverse, and populationstructure was analyzed by using normal distribution from Bhattacharya plot with fullaccommodation on FiSAT II version 3.0. The results of this research indicated thatasymptotic width and growth coefficient for male and female were 7.16 cm, 0.59 cm, and0.96 cm. Therefore, the growth of female pokea was faster than male. Pokea clam populationspread to several size groups that represented as young, adult, and old with median 1.49 and6.01. The dominant length measurement on male and female was relatively different whichpropagated in median 1 cm and 2 cm. Generally, population structure of pokea clam inPohara river was relatively stable.Keyword: pokea, growth, structure, population, river, Pohara