Distribusi Volume Backscattering Strength Ikan Pelagis di Sekitar Rumpon Laut Maluku

Abstract

Laut Maluku merupakan perairan yang memiliki potensi cukup besar dalam sektor perikanan. Beberapa rumpon tersebar di Laut Maluku yang dieksplorasi menggunakan instrumen echosounder single beam SIMRAD EK-15 frekuensi 200 kHz dengan prinsip metode hidroakustik untuk merekam hamburbalik ikan. Metode hidroakustik memberikan informasi berupa echo dari gerombolan ikan atau Volume Backscattering Strength (SV) yang terdistribusi di sekitar rumpon. Penelitian ini bertujuan mendeteksi schooling ikan pelagis menggunakan teknologi hidroakustik berupa nilai hambur balik serta menganalisis hubungan SV ikan pelagis dengan suhu, salinitas, dan arus di sekitar rumpon Laut Maluku. Rumpon di Laut Maluku didominansi oleh ikan pelagis kecil dengan konstruksi rumpon berukuran mencapai 70-100 m bawah air terdiri dari pelampung yang terikat dengan tali apung, atraktor buatan seperti pelepah pinang, dan pemberat. Profil suhu sekitar 29,73 – 26,85 °C, salinitas 34,4 – 34,9 PSU, dan arus 0,2 m/s. Distribusi nilai SV ikan pada ketiga rumpon terkonsentrasi di kedalaman 5 – 20 m dengan nilai SV berkisar -46,53 hingga -52,91 dB yang mengindikasikan bahwa rumpon sangat mempengaruhi dalam distribusi ikan pelagis yang sifatnya bergerombol mengikuti keberadaan atraktor pada rumpon. Kata kunci: Hidroakustik, Rumpon, Volume Bakscattering Strength (SV) Ikan

The Maluku Sea is a water area with considerable potential in the fisheries sector. Several fish aggregating devices (FADs) are scattered in the Maluku Sea, which were explored using a SIMRAD EK-15 single beam echosounder with a frequency of 200 kHz, applying the hydroacoustic method to record fish backscatter. The hydroacoustic method provides information in the form of echoes from fish schools or Volume Backscattering Strength (SV) distributed around the FADs. This study aims to analyze and map both horizontally and vertically the SV values of pelagic fish, temperature, salinity, currents, and characteristics of the FADs in the Maluku Sea waters. Fish aggregating devices (FADs) in the Maluku Sea are dominated by small pelagic fish, with FAD constructions reaching 70–100 meters underwater, consisting of floats tied with floating ropes, artificial attractors such as areca palm fronds, and sinkers. The temperature profile ranges from 29.73 to 26.85 °C, salinity from 34.4 to 34.9 PSU, and currents at 0.2 m/s. The distribution of SV values of fish around the three FADs is concentrated at depths of 5 to 20 meters with SV values ranging from -46.53 to -52.91 dB, indicating that the FADs significantly influence the distribution of pelagic fish, which tend to school following the presence of attractors on the FADs. Keywords: Hydroacoustics, Fish Aggregating Device, Volume Backscattering Strength (SV) of fish