KEPADATAN STOK IKAN DEMERSAL DAN UDANG DI SAMUDERA HINDIA BARAT SUMATERA PADA MUSIM PERALIHAN II

Kepadatan stok ikan merupakan indikasi dari potensi perikanan di suatu wilayah yang sangat penting diketahui. Tujuan tulisan ini membahas tentang laju tangkap, kepadatan stok dan perkiraan biomassa ikan demersal serta udang. Penelitian sumber daya ikan demersal dan udang di Samudera Hindia Barat Sumatera dilakukan dengan menggunakan Kapal Riset Baruna Jaya IV (1.200 GT) pada bulan Oktober dan November 2015 (Musim peralihan II). Penghitungan kepadatan stok menggunakan metode sweept area dengan panjang tali ris atas dari jaring trawl 36 m, kecepatan kapal saat menarik jaring berkisar 2,5 – 3 knot, lama penarikan jaring maksimal 1 jam. Perairan Samudera Hindia Barat Sumatera terdiri dari 151 spesies yang tergolong dalam 59 famili. Famili ikan demersal yang dominan tertangkap (5 besar), yaitu Leiognathidae sebesar 23,6 %, Trichiuridae 9,8%, Haemulidae 8,0%, Engraulididae 6,6%, dan Polynemidae 6,05%. Famili udang yaitu Penaeidae (79,08%), Scyllaridae 19,49%, dan Solenoceridae 1,43%. Rata-rata laju tangkap ikan demersal 205,80 kg/jam, dengan kepadatan stok 6,66 ton/km2 dan udang 2,30 kg/jam dengan kepadatan stok 0,053 ton/km2. Biomassa ikan demersal diperkirakan sebesar 470.122 ton dan udang 3.706 ton. Fish stock density is an index of stock abundance indicating the fish resources potential in a region. This paper discusses the catch rate, stock density and biomass estimates of the demersal fish and shrimp resources. Research on the demersal fish and shrimp resources in the Indian Ocean-Western Sumatera conducted using the Research Vessel Baruna Jaya IV (1200 GT) carried out during October and November 2015 (2nd intermonsoon season). Stock density was estimated through the swept area method. The trawl used has 36 m headrope, trawling speed of 2.5 - 3 knots, and maximum towing time was 1 hour. It was found that the fish resources in the waters of the Indian Ocean-Western Sumatera consisted of 151 species belonging to 59 families. The top five dominant fish families caught were Leiognathidae of 23.6%, Trichiuridae 9.8%, Haemulidae 8.0%, Engraulididae 6.6%, and Polynemidae 6.05%, while the shrimp families were Penaeidae of 79.08%, Scyllaridae 19.49%, and Solenoceridae 1.43%. The average catch rate of demersal fish was 205.80 kg/hour, with a stock density of 6.66 tons/km2 and shrimp of 2.30 kg/hour with a stock density of 5.3 kgs/km2. The estimated biomass of demersal fish was 470,122 tons and shrimp was 3,706 tons.