Sustain or phase out: Transformation of Taiwan’s management scheme on distant water tuna longline fisheries

Marine Policy ◽  
2021 ◽  
Vol 123 ◽  
pp. 104297
Author(s):  
Chao-Chin Huang ◽  
Shui-Kai Chang ◽  
Shiahn-Wern Shyue
Keyword(s):  
Management Scheme ◽  
Longline Fisheries ◽  
Phase Out ◽  
Tuna Longline

scholarly journals KOMPOSISI HASIL TANGKAPAN SAMPINGAN DAN IKAN TARGET PERIKANAN RAWAI TUNA BAGIAN TIMUR SAMUDERA HINDIA (Catch Composition of By-Catch and Target Species on Tuna Longline Fisheries in Eastern Indian Ocean)

2016 ◽  
Vol 5 (2) ◽  
pp. 119
Author(s):  
Dian Novianto ◽  
Budi Nugraha
Keyword(s):  
Indian Ocean ◽  
Eastern Indian Ocean ◽  
Target Species ◽  
Olive Ridley ◽  
Lepidochelys Olivacea ◽  
Bony Fishes ◽  
By Catch ◽  
Catch Composition ◽  
Longline Fisheries ◽  
Tuna Longline

<p>ABSTRACT<br />Tuna longline operations also capture other than tuna species are known as by-catch are caught accidentally due to the ecological linkages. This study aims to identify the species composition of by-catch and try to analyzed the interaction of non-target species with tuna species as the target species on tuna longline fishery in the eastern Indian Ocean. Surveillance was conducted on February 2013-January 2014 by following 7 commercial tuna longliners vessel with fishing operations for 226 days. The results showed there were 36 species, where the target species consists of 4 tuna species (26.11%) and 32 by-catch species consist of by-product (24.08%) and that is not utilized (discards, 49.74%). The Results of by-catch are consists of a lancetfish (Alepisaurus spp., 42.87%), pelagic stingray (Pteroplatytrygon violacea, 22.05%), escolar (Lepidocybium flavobrunneum, 10.22%) and sickle pomfret (Taractichthys steindachneri, 8.21%), while for other species consists of are billfishes (6 species), shark and rays species (10 species), bony fishes (11 species) and turtles (olive ridley).</p><p>Keywords: by-catch, tuna longline, Indian ocean</p><p>-------</p><p>ABSTRAK</p><p>Pengoperasian rawai tuna juga menangkap jenis-jenis lain selain tuna yang dikenal dengan sebutan hasil tangkap sampingan (HTS atau by-catch) yang tertangkap secara tidak sengaja dikarenakan adanya keterkaitan secara ekologi. Penelitian ini bertujuan untuk mengidentifikasi komposisi jenis hasil tangkap sampingan dan mencoba menganalisis hubungan interaksi ikan hasil tangkap sampingan dengan ikan tuna sebagai tangkapan utama (target species) pada perikanan rawai tuna di bagian timur Samudera Hindia. Pengamatan dilakukan pada bulan Februari 2013-Januari 2014 dengan mengikuti kegiatan operasi penangkapan 7 kapal rawai tuna komersial dengan selama 226 hari operasi penangkapan. Hasil penelitian menunjukkanterdapat 35 jenis ikan dan 1 jenis penyu dimana target utama terdiri dari 4 jenis ikan (26,11%) dan hasil tangkapan sampingan 31 jenis ikan dan 1 jenis penyu dimana yang dimanfaatkan (by-product) (24,08%) dan yang tidak dimanfaatkan (discards) (49,74%). Hasil tangkapan sampingan berturut-turut didominasi oleh ikan naga (Alepisaurus spp., 42,87%), pari lemer (Pteroplatytrygon violacea, 22,05%), ikan setan (Lepidocybium flavobrunneum, 10,22%) dan bawal sabit (Taractichthys steindachneri, 8,21%), selanjutnya juga tertangkap jenis paruh panjang (billfish, 6 spesies), jenis cucut dan pari (elasmobranchii, 10 spesies), jenis teleostei (bony fishes,11 spesies) dan penyu lekang (Lepidochelys olivacea).</p><p><br />Kata kunci: Hasil tangkap sampingan, rawai tuna, Samudera Hindia</p>

scholarly journals BEBERAPA PARAMETER POPULASI IKAN PEDANG (Xiphias gladius) DI SAMUDERA HINDIA BAGIAN TIMUR

2017 ◽  
Vol 8 (2) ◽  
pp. 117
Author(s):  
Bram Setyadji ◽  
I Wayan Arthana ◽  
I Wayan Kasa
Keyword(s):  
Indian Ocean ◽  
Stock Assessment ◽  
Total Mortality ◽  
Growth Parameter ◽  
Assessment Model ◽  
Eastern Indian Ocean ◽  
Optimum Level ◽  
Xiphias Gladius ◽  
Longline Fisheries ◽  
Tuna Longline

Komposisi hasil tangkapan ikan berparuh (Istiophoridae dan Xiphiidae) menduduki peringkat kedua terbesar setelah tuna (Thunnus sp.) pada perikanan rawai tuna. Sekitar 90% jenis ikan berparuh yang di daratkan didominasi oleh ikan pedang (Xiphias gladius), yang mana merupakan hasil tangkap sampingan dari perikanan rawai tuna, terutama di Samudera Hindia bagian timur. Meskipun dikategorikan sebagai ikan dengan nilai ekonomis tinggi, akan tetapi studi mengenai parameter populasi untuk spesies ini masih terbatas, terutama di Indonesia. Penelitian ini bertujuan untuk menduga parameter pertumbuhan, laju mortalitas dan laju ekploitasi ikan pedang berdasarkan data ukuran panjang. Model pengkajian stok menggunakan data frekuensi panjang dipilih karena ketersediaan dan kemudahan pengambilan data tersebut dibandingkan dengan metode lainnya. Penelitian ini menggunakan data pemantau ilmiah tahun 2005 sampai dengan 2014 dan data pengamatan harian pendaratan tuna dan sejenisnya tahun 2002 sampai dengan 2014 di Samudera Hindia. Hasil penelitian menunjukkan pertumbuhan ikan pedang relatif cepat, terutama pada awal masa pertumbuhan dengan nilai K = 0,12/tahun, t0 = -0,76025 tahun dan L = 302,4 cmFL. Nilai F (0,28/tahun) sedikit lebih besar daripada nilai M (0,24/tahun), yang berarti kematian ikan pedang lebih banyak disebabkan oleh penangkapan. Nilai E sebesar 0,55 mengindikasikan bahwa ikan pedang yang tertangkap oleh armada rawai tuna di Samudera Hindia berada pada kondisi optimum. Billfishes (Istiophoridae and Xiphiidae) are the second largest catch in tuna longline fisheries. About 90% of billfishes landed dominated by swordfish (Xiphias gladius) which was a by-catch from tuna longline fisheries, especially in eastern Indian Ocean. Despite of its high economic value, study on stock assessment for this species is limited, especially in Indonesia. The catch-at-size based stock assessment model was applied, to its availability and ease on collecting the data. The Objectives of this study are to estimate growth parameter, mortality rate and exploitation rate based on catch-at-size data. The primary data was obtained from scientific observer program from 2005 to 2014 and port sampling data from 2002 to 2014. The result showed that swordfish were relatively fast growth, especially on their early age (K = 0.12/year) with t0 estimated around -0.76 year and Linf about 302.4 cmLJFL. The estimated of total mortality (Z), natural mortality (M) and fishing mortality (F) from the model were 0.52/year, 0.24/year and 0.28/year respectively. The explitation rate of swordfish in the eastern Indian Ocean is on optimum level (E=0.55).

scholarly journals Biodiversity in the bycatch community of Chinese tuna longline fisheries in the Pacific Ocean

2020 ◽  
Vol 24 ◽  
pp. e01276
Author(s):  
Jiaqi Wang ◽  
Xiaodi Gao ◽  
Luoliang Xu ◽  
Libin Dai ◽  
Jessica Chen ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Longline Fisheries ◽  
Tuna Longline

scholarly journals Stock depletion of yellowfin tuna Thunnus albacares (Bonnaterre 1788) in the Northeastern Indian Ocean

2021 ◽  
Vol 322 ◽  
pp. 05004
Author(s):  
Bram Setyadji ◽  
Hety Hartaty ◽  
Arief Wujdi ◽  
Ririk K. Sulistyaningsih
Keyword(s):  
Indian Ocean ◽  
Data Collection ◽  
Relative Abundance ◽  
Yellowfin Tuna ◽  
Coastal Communities ◽  
Thunnus Albacares ◽  
The Indian Ocean ◽  
Stock Depletion ◽  
Longline Fisheries ◽  
Tuna Longline

The stock of yellowfin tuna (Thunnus albacares) has been in a declining trend in the last five years. Although the noticeable decline mainly occurred in the western part of the Indian Ocean, uncertainty lingers on how this phenomenon will affect the opposite leg. The study aimed to investigate the dynamics of stock through monitoring several indicators by utilizing logbooks, scientific port sampling, and observer data available. The result showed that both relative abundance and estimated catch trend are declining in recent years, a sign that the negative global inclination also influences Indonesian tuna longline fisheries. Further studies are needed to understand whether this phenomenon also impacts other gears. Hence, mitigation on conserving the resource by reducing the catch and strengthening the data collection should be the priority to maintain the livelihood and welfare of many coastal communities.

scholarly journals Comparison of Catch Efficiency between the Use of Circle and Tuna Hooks in Taiwan’s Tuna Longline Fishery in the Eastern Pacific Ocean

2020 ◽  
Author(s):  
Chao-ching Chen ◽  
Hsin-Zong Lin
Keyword(s):  
Immersion Time ◽  
Negative Impact ◽  
Survival Rates ◽  
Sea Turtle ◽  
Yellowfin Tuna ◽  
Eastern Pacific Ocean ◽  
Turtle Conservation ◽  
Sea Turtle Conservation ◽  
Longline Fisheries ◽  
Tuna Longline

Taiwan is the world&rsquo;s leading country regarding tuna longline fisheries; the combined catches with those from Japan account for more than half of the global total. However, the bycatch of sea turtles, seabirds, and dolphins in longline fisheries has attracted international concern. Regarding sea turtle conservation, the use of circle hooks in longline fisheries will inevitably become a trend. Meanwhile, Taiwanese fishermen are concerned whether the use of circle hooks will have a negative impact on the catch efficiency of target species. This study was conducted to compare the catch efficiency of circle and tuna hooks by the Taiwanese commercial tuna longline fishing vessels in the eastern Pacific Ocean. The results indicated that if the effects of immersion time were considered, the catch rates of all groups were the same between 4.2-sun circle and tuna hooks. However, the catch rate of 4.0-sun circle hooks was significantly higher than the two types of 4.2-sun circle and tuna hooks. Regarding survival rates, fish caught with circle hooks showed higher survival rates than tuna hooks for total commercial fish, tunas and yellowfin tuna (Thunnus albacares). However, the survival rate was only determined at haulback; the relationship between survival rate and immersion time still needs further investigation. Regarding catch sizes, there were no significant differences in the sizes of bigeye (Thunnus obesus) and yellowfin tuna between circle and tuna hooks. But based solely on mean weight, the value of yellowfin tuna caught using circle hooks may be higher than those using tuna hooks. In summary, the circle hooks used in this study did not show a negative impact on the catch efficiency of Taiwanese longline fisheries, and could show a superior performance than that of tuna hooks. These results could be actively promoted in the industry through the education and training of fishermen; thus enabling Taiwan to comply with international sea turtle conservation trends.

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