POTENSI REKRUT IKAN BONTI-BONTI (Paratherina striata Aurich) DI DANAU TOWUTI, SULAWESI SELATAN

Abstract

Ikan bonti-bonti (Paratherina striata) selain endemik, statusnya tergolong rawan punah (vulnerable species) dan hanya terdapat di Danau Towuti dan Danau Mahalona. Masyarakat di sekitar danau memanfaatkan ikan ini sebagai ikan konsumsi, ikan hias, dan bahan pakan hewan. Populasi ikan ini dikhawatirkan mengalami penurunan, diduga karena degradasi kualitas lingkungan dan penangkapan ikan yang cenderung intensif. Penelitian ini bertujuan untuk mengkaji potensi rekrut ikan bonti-bonti sebagai dasar pengelolaannya. Pengamatan dilakukan di Danau Towuti setiap bulan selama 12 bulan dari bulan Mei 2006-April 2007. Contoh ikan diperoleh menggunakan jaring insang eksperimental dengan ukuran mata jaring 0,625, 0,75, 1,0, dan 1,25 inci yang dioperasikan di lima stasiun (Tanjung Bakara; inlet Danau Towuti; Pulau Loeha; outlet Danau Towuti dan Beau). Potensi rekrut ikan dapat dilihat dari nisbah kelamin, diameter telur, fekunditas, dan indeks kematangan gonad. Hasil penelitian memperlihatkan bahwa nisbah kelamin total ikan bonti-bonti jantan dan betina 1,0:0,9. Fekunditasikan bonti-bonti 818-6.051 butir. Diameter telur ikan bonti-bonti berkisar antara 0,01-1,50 mm. Nilai indeks kematangan gonad ikan bonti-bonti jantan dan betina paling tinggi dijumpai di stasiun II, masing-masing 3,96 dan 6,77%. Ditinjau dari fekunditas, potensi rekrut ikan bonti-bonti lebih tinggi dibandingkan ikan Telmatherinidae lain. Secara temporal, nilai rata-rata indeks kematangan gonad tertinggi pada ikan jantan terjadi pada bulan Mei dan Nopember dengan nilai 2,09±1,36% dan 1,85±1,06%, demikian pula pada ikan betina dengan nilai 3,39±1,47 dan 3,47±1,37%. Rekruitmen ikan bonti-bonti terjadi setiap bulan dengan periode tertinggi antara bulan Oktober-Nopember. Bonti-bonti (Paratherina striata), is one of endemic and vulnerable fish in Lake Towuti and Mahalona. Bonti-bonti have been utilized by people around the lake as consumption fish; ornamental fish and as raw material for animal feed. The population tend to decrease due to environmental quality deterioration and increasing exploitation. This study was aimed to reveal the recruit potential of bontibonti as the foundation for its management. This research was conducted in Lake Towuti, South Sulawesi from May 2006 to April 2007. Samples were collected monthly at five stations (Tanjung Bakara; Inlet of Lake Towuti; Pulau Loeha; Outlet of Lake Towuti, and Beau) using experimental gillnet sized 0.625, 0.75, 1.0, and 1.25 inches. Recruitment potential could be evaluated from sex ratio, egg diameter, fecundity, and gonad maturity index. Total sex ratio of male and female bonti-bonti are 1.0:0.9. Fecundity of bonti-bonti are 818-6.051. Egg diameter of bonti-bonti range from 0.01-1.50 mm. Gonad maturity index value of male and female was found highest at station II (inlet of Lake Towuti) as high as 3.96 and 6.77% respectively. Based on fecundity, recruitment potential of bontibonti is higher compared to the other Telmatherinid. Temporally, the average value of gonad maturity index was found highest on male in May and November with the values of 2.09±1.36% and 1.85±1.06%, and for female with the values of 3.39±1.47 and 3.47±1.37%. Fish recruitment occured each month with the highest period occur in October-November.