BEBERAPAASPEKBIOLOGI IKANBELOSO(Sauridamicropectoralis) DI PERAIRANUTARAJAWATENGAH

Abstract

Indeks kelimpahan stok ikan beloso (Saurida micropectoralis) di Laut Jawa cenderungmengalami penurunan dari tahun ke tahun dan untuk mencegahnya perlu bahan masukan yang bersumber dari hasil penelitian yang dijadikan sebagai dasar pengelolaannya. Penelitian dilakukan untukmengkaji beberapa aspek biologimeliputi hubungan panjangberat, nisbah kelamin, tingkat kematangan gonad, panjang pertama kali tertangkap dan panjang pertama kali matang gonad, serta kebiasaan makan ikan beloso. Penelitian dilakukan pada bulanApril–Agustus 2009 di perairan utara Jawa Tengah. Hasil penelitian menunjukkan bahwa nisbah kelamin ikan jantan dan betina berada dalam keadaan tidak seimbang. Pertumbuhan ikan beloso bersifat allometrik positif, dimana pertambahan berat lebih cepat dibandingkan pertumbuhan panjangnya dan tingkat kematangan gonad (TKG) ikan beloso didominasi oleh stadium I. Panjang pertama kali ikan beloso tertangkap lebih kecil dari panjang pertama kali matang gonadnya (Lc < Lm) sehingga akan mengancam kelestariaannya. Ikan beloso bersifat karnivora, dimana makanan utamanya adalah potongan ikan dasar, cumi, dan teri.

Index of stock abundance of Lizardfish (Saurida micropectoralis) in Java Sea tend to decreased from year to year. The decline was expected because of the potential of Lizardfish decreasing but the effort continue to rise. The objective of this study is to assess the biological aspects including length-weight relationship, sex ratio, gonadal maturity stage, length of first capture (Lc) and length of first mature (Lm), and feeding habit of Lizardfish in north waters of Central Java. This study was conducted from April to August 2009 in north waters of Central Java. Results showed that the sex ratio between males and females was 1:0,97. Based on Chi-square test it is showed that sex ratio is not balanced. The growth of Lizardfish indicated positive allometric where the weight growth more faster than its length growth. The gonadalmaturity stage of Lizard fish is dominated by the first stage. The length of first capture of Lizardfish was under the length of first mature (Lc < Lm) so that will threaten its sustainability. Lizardfish was indicated carnivorous species where its main food are part of demersal fishes, squids and anchovies.