ESTIMASI PARAMETER POPULASI DAN RASIO POTENSI PEMIJAHAN TONGKOL KOMO (Euthynnus affinis, Cantor 1849) DI PERAIRAN SELATAN LOMBOK

Abstract

Tongkol komo (Euthynnus affinis) merupakan salah satu komoditas ekonomis tinggi perikanan tuna neritik, terutama bagi armada tuna skala kecil. Seiring dengan meningkatnya intensitas penangkapan pada satu dekade terakhir, diperlukan kajian kuantitatif terkait keberlangsungan stok. Akan tetapi, minimnya data yang tersedia pada perikanan jenis ini merupakan tantangan terbesar dalam melakukan usaha pengelolaan. Penelitian ini bertujuan untuk menduga parameter populasi dan rasio potensi pemijahan (SPR) berbasis ukuran panjang, sebagai titik acuan biologis kondisi stok dalam menghadapi tekanan penangkapan. Total 1.321 data ukuran panjang dikumpulkan secara acak setiap bulan selama Januari hingga Desember 2016 di Tanjung Luar. Parameter populasi meliputi pertumbuhan, kematian, rekrutmen, dan laju pemanfaatan diestimasi dengan metode ELEFAN. Analisis SPR juga dilakukan dengan melibatkan parameter reproduksi yang disintesis dari penelitian sebelumnya dengan paket LB-SPR. Hasil penelitian menunjukkan bahwa formula pertumbuhan von Bertalanffy diekspresikan dengan persamaan Lt = 85,0 (1-e-0,7 (t+0,173)). Meskipun rata-rata sampel tongkol komo diprediksi telah matang gonad/memijah (SL50>L50), namun sumberdaya tongkol komo mengalami tekanan yang tergolong tinggi dan mengganggu rekrutmen individu baru ke dalam stok yang diindikasikan dengan parameter lainnya seperti rasio mortalitas penangkapan relatif (F/M) = 2,15, laju eksploitasi (E) = 0,68, dan SPR = 23%. Oleh karena itu, diperlukan penyusunan pengelolaan yang efektif untuk kelestarian perikanan. Eastern little tuna or commercially known as kawakawa is listed as one of the most economically important species of neritic tuna, especially caught by small-scale tuna fisheries. Increasing fishing pressure in the last decade should be responded by a quantitative analysis on its stock. The problem arises when this typical fishery usually possesses limited time-series data. This study intended to estimate population parameters and spawning potential ratio (SPR) as a biological reference point to state the healthiness of fishery corresponding to the fishing pressure around coastal areas. A total of 1,321 length measurement data were randomly sampled monthly from January to December 2016 in Tanjung Luar. Population parameters including growth, mortality, recruitment, and exploitation rate were estimated by applying the ELEFAN method. SPR analysis was also carried out by involving reproduction parameters synthesized from previous studies using the LBSPR package. The results showed that the von Bertalanffy growth functions were expressed by the equation Lt = 85.0 (1-e-0.7(t + 0.173)). Although the majority of kawakawa was predicted in maturity as indicated by SL50>L50, high exploitation has occurred to the fishery that can be interfered the recruitment to the stock, as confirmed by other parameters, such as relative fishing mortality (F/M) = 2.15, exploitation rate (E) = 0.68, and SPR = 23%. Hence, the establishment of appropriate management strategies is needed to aim fishery sustainability.

Characteristics of Tuna, Small Tuna and Skipjack (Tts) Fishery in Kutaraja Ocean Fishing Port, Aceh

“…Komo tuna is able to reach the fork length and maximum age of 80.75 cm and 4.29 years, respectively, the fork length reaches 47.6 cm, 66.4 cm, 75.8 cm, and 80.4 at age. 1, 2, 3 and 4 consecutive years (Wujdi et al, 2020) The fish caught in FADs show relatively the same size every month, this is thought to be due to the fishing area around FADs. The fish that are in FAD tend to be in schooling, so that the size caught is relatively uniform.…”

The Fishing Grounds and the Exploitation Status of Kawakawa (Euthynnus affinis) in Java Sea, Indonesia

“…The size structure in other areas were bigger than in this area, i.e. in Maharastra, India, 26-73 cm (Zafar-Khan 2004), in Kerala, India, 30-64 cm (Pillai et al 2007), in Iran waters 28-88 cm (Kaymaram and Darvishi 2012), in India 14-88 cm (Rohit et al 2012), in West Sumatera 30-60 cm (Jatmiko et al 2014), in Malacca Strait 16-60 cm (Wagiyo et al 2017) and 20-56 cm (Faizal et al 2017), in Tanjung Luar, West Nusa Tenggara, 24-71 cmFL (Agustina et al 2018), in Lampulo, Aceh, 17-59 cm (Salmarika et al 2018), in East Indian Ocean 28-56 cm (Ekawaty and Jatmiko 2018), and in South Lombok 21-77 cm (Wujdi et al 2020).…”

“…Upon reaching 1 year old, the size of the fish in Java Sea were mostly smaller than the same fish in other areas. At 1 year old, the fish in Maharastra waters, India, reached 44.6 cm in size (Zafar-Khan 2004), in Iran 49 cmFL (Kaymaram and Darvishi 2012), in India 42.7 cm (Rohit et al 2012), and in South Lombok, West Nusa Tenggara, 47.6 cm (Wujdi et al 2020). The difference in the achieved fish size (length infinity) was due to difference race (genes), food availability, and the contributing environmental condition that affected the rate of the species individual growth.…”

Kondisi Stok Ikan Karang Di Kawasan Konservasi Perairan TWP Gita Nada, Provinsi Nusa Tenggara Barat

“…Ukuran panjang ikan yang ditangkap dan didaratkan oleh nelayan dapat memberikan pengaruh terhadap tingkat eksploitasi (E), tekanan penangkapan (F/M) (Agustina et al 2018;Saranga et al 2019), serta kondisi kesehatan stok ikan (berdasarkan nilai spawning potensial ratio/SPR (Koolkalya et al 2017;Pulungan et al 2022). Struktur ukuran panjang ikan yang mengarah pada ukuran yang lebih besar akan menyebabkan E dan F/M menjadi lebih kecil, dimana hal tersebut merupakan indikasi bahwa stok ikan berada dalam kondisi sehat.…”