BIOLOGI REPRODUKSI IKAN MADIDIHANG (Thunnus albacares Bonnatere 1788) DI TELUK TOMINI - Siti Mardlijah; Mufti Petala Patria (Pusat Riset Perikanan, BRSDM KP., 2012)
Penelitian biologi reproduksi bertujuan untuk mengetahui perkembangan gonad dan panjang pertama kali matang gonad ikan madidihang yang tertangkap di perairan Teluk Tomini. Jumlah sampel telur sebanyak 74 contoh dan sampel testes sebanyak 90 contoh dikumpulkan melalui tempat pendaratan ikan di Marisa, Gorontalo pada tahun 2007. Tingkat kematangan gonad diamati secara visual dan pembuatan preparat histologis serta analisis Gonado Somatic Index (GSI). Hasil penelitian ini menunjukkan bahwa pemijahan ikan madidihang diperkirakan terjadi pada bulan Desember dan panjang pertama kali matang gonad pada ukuran 94 cm FL. Nisbah kelamin ikan madidihang jantan dan betina adalah seimbang. The objective of research on reproductive biology of yellowfin tuna is to study gonad development and its length at first maturity.Gonad development were determined through the examination of 74 yellowfin ovaries samples and 90 testes samples collected from Marisa, Gorontalo in 2007. Gonad maturity stages were identified histologically. Sexual maturity stages was identified through visual analyzed, preparation on histology and Gonado Somatic Index (GSI). The result showed that spawning season of yellowfin tuna in Tomini Bay occured in December.Meanwhile length at first maturity at 94,8 cm FL. The ratio of males and females of yellowfin tuna is well-balanced.