PERIKANAN TUNA SIRIP KUNING (Thunnus albacares Bonnaterre, 1788) PADA ARMADA TONDA DI SAMUDERA HINDIA SELATAN JAWA

Abstract

Tuna sirip kuning (Thunnus albacares) merupakan hasil tangkapan terbanyak dibandingkan dengan jenis tuna lainnya di Indonesia. Ketersediaan stok tuna sirip kuning di Samudra Hindia, pada saat ini, diperkirakan dalam keadaan lebih tangkap. Oleh karena itu, pengelolaan secara tepat dan bertanggungjawab penting dilakukan untuk melindungi spesies tuna, salah satu caranya dengan mengkaji alat tangkap yang digunakan. Tulisan ini bertujuan untuk mengungkapkan produktivitas dan hasil tangkapan armada tonda, serta struktur ukuran dan hubungan panjang bobot ikan tuna sirip kuning yang di daratkan di selatan Jawa. Komposisi tangkapan tertinggi dari armada tonda diseluruh pendaratan ikan tuna di selatan Jawa terdiri atas tuna sirip kuning dan cakalang. Analisis CPUE menunjukkan hasil yang fluktuatif di setiap lokasi pendaratan tuna sirip kuning di Selatan Jawa. Tuna sirip kuning yang tertangkap di selatan Jawa dengan armada tonda sebagian besar adalah ikan yang belum layak tangkap karena berukuran kurang dari 100 cmFL. Struktur ukuran panjang tuna sirip kuning yang tertangkap semakin ke Timur semakin panjang ukurannya. Pola pertumbuhan tuna sirip kuning yang tertangkap di Binuangeun memiliki pola isometrik, PPN Palabuhanratu bersifat allometrik Positif, PPP Sadeng, P2SKP Pacitan, PPN Prigi dan P2SKP Sendang Biru bersifat allometrik negatif. Yellowfin tuna (Thunnus albacares) is the largest catch compared to other tuna species in Indonesia. The availability of yellowfin tuna stock in the Indian Ocean, at present, is estimated to be in overfished condition. Therefore, proper and responsible management is important to protect the species. One of the ways is by studying the used fishing gear. This paper aims at determining vessel’s productivity, as well as composition, size structure and length-weight relationship of yellowfin tuna catches from troll line fleet in the Indian Ocean part of south Java. The highest catch of tuna in all of the troll line landing places was yellowfin tuna, following by skipjack tuna. CPUE analysis showed fluctuating results at each landing site. Yellowfin tuna sizes caught by troll line fleet were mostly less than 100 cmFL and categorized as should not be properly caught. Geographically, getting to the east the average size of the catches tend to be larger. The growth pattern of yellowfin tuna catches landed in Binuangeun was isometric; Palabuhanratu was positive allometric; while those landed in Sadeng, Pacitan, Prigi and Sendang Biru were negative allometric.

Length-weight relationship and relative condition factor of yellowfin tuna (Thunnus albacares: Bonnaterre, 1788) West Sabah Waters

“…Although the parameters a derived from our study were consistent with studies conducted in other areas, b values were slightly lower compared to the estimates from Pratibha and Rammohan [17] and Jamitko et al [18] . Nevertheless, the linear regressions values (b) for yellowfin tuna caught in our study align with those reported in other areas, such as the Southeast coast of India [23] and West Java, Indonesia [16,24,25] . The exponential coefficient (b) in the length-weight relationship varies among species due to environmental factors.…”

“…The length frequency distribution of yellowfin was 20-170 cm with a weight range of 0.2-82 kg. Meanwhile, a study from Molluca Sea, Indonesia showed a length range of yellowfin from 85-174 cm and a weight range of 10-75 kg [15] , length range of yellowfin in West Java, Indonesia from 23-168 cm [16] .…”

“…Consequently, the variations in b values can be attributed to either a single factor or a combination of multiple factors [8,9] . [2] West Java, Indonesia 0.00002 3.029 0.964 NA Jamitko et al [18] West Java, Indonesia 0.00004 2.842 0.957 7,550 Nugroho et al [24] Southeast coast of India 0.0403 (male) 2.78 (male) 0.953 495 Mariasingarayan et al [23] 0.0647 (female) 2.82 (female) 0.975 659 West Java, Indonesia 0.0191 2.9991 0.97 3,456 Agustina et al [16] West Java, Indonesia 0.0001 2.7003 0.95 200 Patanda et al [25] West Sabah waters, South China Sea 0.00003 2.8893 0.957 11,650 Present study…”

Estimated production, catch per unit effort, biological aspects of tuna, skipjack, and small tuna in North Sumatra

“…Most of the yellowfin tuna caught in southern Java are fish that have not been caught because they are less than 100 cmFL in size. The structure of the length of the yellowfin tuna caught the longer to the east, the longer the size [14]. Most of the yellowfin tuna landed by purse seine were of a smaller size than predicted, YFT caught in the Indian Ocean are in the range of length 131-140 cm and weight 46-50 kg [15], and in the range of length 23-168 [14].…”

“…The structure of the length of the yellowfin tuna caught the longer to the east, the longer the size [14]. Most of the yellowfin tuna landed by purse seine were of a smaller size than predicted, YFT caught in the Indian Ocean are in the range of length 131-140 cm and weight 46-50 kg [15], and in the range of length 23-168 [14]. The fish suitable for catching is the size of the fish at first gonad maturity (length at first maturity = Lm) [16].…”