ANALISIS PERTUMBUHAN DAN LAJU EKSPLOITASI IKAN TONGKOL ABU-ABU, Thunnus tonggol (Bleeker, 1851) DI PERAIRAN LAUT JAWA

Abstract

Tongkol abu-abu atau longtail tuna (Thunnus tonggol) salah satu jenis ikan tuna neritik sebagai target penangkapan armada pukat cincin, jaring isang, dan pancing di Laut Jawa. Penelitian ini bertujuan untuk mengetahui parameter pertumbuhan, umur dan mortalitas ikan tongkol abu-abu untuk penyusunan strategi pengelolaannya. Pengumpulan data frekuensi panjang dan bobot ikan dilakukan di Pelabuhan Perikanan Nusantara (PPN) Pekalongan pada Januari – Nopember 2014. Hasil penelitian menunjukkan hubungan panjang-bobot ikan tongkol abu-abu bersifat isometrik dan indek kecepatan pertumbuhan 3,46/tahun. Ikan dapat tumbuh hingga mencapai panjang asimtotik (L) = 85 cm dengan laju pertumbuhan (K) sebesar 0,4/tahun. Umur teoritis pada saat panjang ikan sama dengan nol (t0) adalah 0,046 tahun. Umur maksimal diduga 15 tahun. Mortalitas alami (M) sebesar 0,61/tahun, mortalitas karena penangkapan (F) 1,01/tahun, mortalitas total (Z) 1,62/tahun. Tingkat eksploitasi (E) sebesar 0,59 berarti bahwa pemanfaatan ikan tongkol abu-abu di Laut Jawa cenderung sudah penuh (fully exploited).Longtail tuna as one of neritic tuna species are commonly caught by purse seine, gill net and hand line in java sea.. This research activity aims to determine population parameters i.e. growth, mortality and its exploitation rate that can contribute to strengthen database on preparation its harvest strategy. The Collecting of length and weight data were conducted at Pekalongan fishing port during period of January to November 2014. The Long-weigth relationship was isometric and growth performance index was 3.46/year. The asymptotic length rate (L) was 85 cmFL, growth rate (K) was 0.4/year and zero age (t0) was 0.046 year. This length is reached allegedly at the 15 years age. Natural mortality (M) was 0.6/year, fishing mortality (F) was 1.01/year, total mortality (Z) was 1.62/yera. The exploitation rate (E) was 0.59, it means exploitation of longtail tuna in the Java Sea tend to highly exploited.

PERIKANAN PURSE SEINE DI LAUT JAWA YANG BERPANGKALAN DI PPN PEKALONGAN, STUDI KASUS : TONGKOL ABU-ABU (Thunnus tonggol)

“…Laut Jawa (WPPNRI 712) merupakan perairan territorial, kegiatan penangkapan sebagian besar dilakukan di perairan utara Jawa, dengan potensi ikan pelagis yang cukup besar (Suman et al 2017). Pada tahun 2014 produksi perikanan tangkap di Laut Jawa terbesar di seluruh Indonesia yaitu (17,91% dari total produksi Indonesia) 6.037.654 ton (Restiangsih & Hidayat 2018).…”

Short Communication: Genetic structure of Longtail Tuna Thunnus tonggol (Bleeker, 1851) in Java Sea, Indonesia

“…In one of the T. tonggol study in Java Sea, it is mentioned that the conditions of this species in the areas are listed as fully exploited (Restianingsih and Hidayat 2018), which then rise a sustainable fisheries issue because Indonesia and other countries such as Thailand, Malaysia, and Iran are the countries that have a high contribution on the T. tonggol fisheries in the world (Griffiths et al 2010;Abdussamad et al 2012;Darvishi et al 2018). Another study conducted in Southwest Aceh indicated that the condition of T. tonggol population in that area indicated a low vulnerability status and high productivity rate, which signifies that the Longtail Tuna population in Southwest Aceh is still in a good level of resource sustainability category (Rahma et al 2019).…”

“…Longtail Tuna usually found around Indo-Pacific waters (Sharma et al 2012;Kunal et al 2014;Froese and Pauly 2019). In Indonesia, T. tonggol species is easy to find within the area of Java Sea, including in the Fisheries Management Area-712 (FMA-712) with a total area of 320.000 km 2 (Restianingsih and Hidayat 2018); Kep-Men KKP 2016). In their report, it is also mentioned that there is indication of full exploitation of Longtail Tuna population within Java Sea (Restianingsih and Hidayat 2018), which will impact the sustainable fisheries of this species.…”

“…In Indonesia, T. tonggol species is easy to find within the area of Java Sea, including in the Fisheries Management Area-712 (FMA-712) with a total area of 320.000 km 2 (Restianingsih and Hidayat 2018); Kep-Men KKP 2016). In their report, it is also mentioned that there is indication of full exploitation of Longtail Tuna population within Java Sea (Restianingsih and Hidayat 2018), which will impact the sustainable fisheries of this species. Furthermore, a study by Sharma et al (2012), showed that the status of Longtail Tuna in Indo-Pacific has been approaching overfishing category.…”

“…Several studies of Longtail Tuna (T. tonggol) has been conducted by taking the total catch and total length on the landing sites (Abdussamad et al 2012;Restianingsih and Hidayat 2018); however, fisheries landing reports may not always represent the actual data, due to the species missidentification thus lead to miss-calculation of the number of catch reports (Pauly and Froese 2012). Therefore, to add more information on this tuna landing reports, genetic studies were conducted.…”