Distribusi Nilai Target Strength dan Densitas Ikan Demersal berdasarkan Suhu di Perairan Pulau Lancang

Abstract

Sumber daya ikan demersal di Perairan Pulau Lancang tergolong sangat melimpah yaitu mencapai 59.478 ind/1000 m³. Kelimpahan tersebut dapat dimanfaatkan secara berkelanjutan dengan pengelolaan optimal yang didukung oleh data distribusi sumber daya ikan demersal. Penelitian ini bertujuan menggambarkan nilai target strength dan densitas ikan demersal berdasarkan strata kedalaman, serta memetakan distribusi spasial berdasarkan suhu di Perairan Pulau Lancang dengan memanfaatkan metode hidroakustik. Data yang digunakan merupakan data akustik hasil sounding instrumen Simrad EK15 frekuensi 200 kHz, yang kemudian dianalisis menggunakan metode integrasi echo. Hasil penelitian menunjukkan bahwa nilai target strength ikan demersal berkisar antara -59,9 dB hingga -37,0 dB dengan frekuensi tertinggi pada rentang -55 hingga -52 dB. Peningkatan nilai target strength dan densitas ikan demersal teridentifikasi pada kedalaman perairan 10–20 meter, yang mencerminkan keberadaan organisme berukuran lebih besar dan beragam, serta peningkatan kategori densitas dari sedang hingga sangat melimpah. Distribusi spasial ikan demersal dipengaruhi oleh suhu dasar perairan dan kedalaman dengan kondisi habitat paling optimal ditemukan pada suhu 29,1–30,2 °C dan kedalaman perairan 15–20 meter.

Demersal fish resources in the waters of Lancang Island are classified as very abundant, reaching 59,478 ind/1000 m³. This abundance can be utilized sustainably with optimal management supported by demersal fish resource distribution data. This study aims to describe distribution of target strength (TS) and demersal fish density with five stratification, as well as to map their spatial distribution based on temperature using hydroacoustic methods. The data used were acoustic recordings from the Simrad EK15 instrument operating at 200 kHz, which were then analyzed using the echo integration method. The results showed that the target strength values of demersal fish ranged from -59.9 dB to -37.0 dB, with the highest frequency occurring in the -55 to -52 dB range. An increase in TS values and fish density was identified at depths of 10–20 meters, indicating the presence of larger and more diverse organisms, along with higher density categories ranging from moderate to very abundant. The spatial distribution of demersal fish was influenced by bottom temperature and depth, with the most optimal habitat conditions found at temperatures of 29.1–30.2 °C and depths of 15.1–20 meters.