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 terus mengalami tekanan sejalan dengan peningkatan aktivitas kegiatan penangkapan dan  menurunnya kualitas perairan.  Penelitian ini bertujuan untuk mengetahui struktur dan pertumbuhan populasi kerang pokea di Sungai Pohara Sulawesi Tenggara.  Penelitian ini dilaksanakan di segmen muara Sungai Pohara selama setahun dari bulan Maret 2007-Februari 2008. Parameter populasi (L∞ dan K) dan to masing-masing dianalisis dengan menggunakan pergerakan modus frekuensi panjang dan nilai L0=0.025.  Pola pertumbuhan dianalisis menggunakan inverse von Bertalanffy sedangkan struktur populasi dianalisis menggunakan distribusi normal dari plot Bhattacharya yang secara keseluruhan terakomodasi pada program FiSAT II versi 3.0. Hasil penelitian menunjukkan bahwa lebar asimtotik dan koefisien pertumbuhan jantan dan betina masing-masing yaitu 7.16 cm, 0.59 dan 6.92 cm, 0.96. Oleh karenai tu, pertumbuhan pokea betina lebih cepat dibandingkan pokea jantan.  Populasi kerang pokea tersebar pada berbagai kelompok ukuran yang mewakili ukuran muda, dewasa dan tua dengan nilai tengah berada pada 1.49 dan 6.01 yang menyebar pada tiga kelompok ukuran.  Kelompok ukuran dominan pada jantan betina relatif berbeda yang tersebar pada nilai tengah masing-masing 1cm dan 2cm.  Secara umum, struktur populasi pokea di Sungai Pohara relatif stabil.Key word : pokea, pertumbuhan, struktur, populasi, sungai, PoharaAbstractPokea clam was fresh water bivalve that lived on well into estuary segments.  This bivalve have experienced in under pressure as activity increase in fishing events and decrease in water quality. This research aimed to understand the structure and growth population of pokea clam in Pohara river on Southeast Sulawesi. This research was conducted in estuary segment 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 and Lo=0.025. Growth pattern was analyzed by using von Bertalanffy inverse, and population structure was analyzed by using normal distribution from Bhattacharya plot with full accommodation on FiSAT II version 3.0. The results of this research indicated that asymptotic width and growth coefficient for male and female were 7.16 cm, 0.59 cm, and 0.96 cm. Therefore, the growth of female pokea was faster than male. Pokea clam population spread to several size groups that represented as young, adult, and old with median 1.49 and 6.01. The dominant length measurement on male and female was relatively different which propagated in median 1 cm and 2 cm. Generally, population structure of pokea clam in Pohara river was relatively stable.Keyword: pokea, growth, structure, population, river, Pohara