scholarly journals STANDARDIZING CPUE OF ALBACORE TUNA (Thunnus alalunga Bonnaterre, 1788) ON TUNA LONGLINE FISHERY IN EASTERN INDIAN OCEAN

2017 ◽  
Vol 23 (1) ◽  
pp. 29
Author(s):  
Fathur Rochman ◽  
Bram Setyadji ◽  
Arief Wujdi
Keyword(s):  
Indian Ocean ◽  
Relative Abundance ◽  
Eastern Indian Ocean ◽  
Series Data ◽  
Longline Fishery ◽  
Albacore Tuna ◽  
Fishing Vessels ◽  
Abundance Indices ◽  
Thunnus Alalunga ◽  
Tuna Longline

Albacore (Thunnus alalunga) is the third dominant catch of Indonesian tuna longline fishery operating in the eastern Indian Ocean. The percentage production of albacore catch was reaching up 6% of the total catch of tuna groups in Indonesia. Thi study aims to examine a relative abundance indices using standardized catch per unit of effort (CPUE) of longliner based on albacore tuna. This information will give a valuable input and information to support stock assessment particularly in the regional basis. In this study, we use Generalized Linear Model (GLM) with Tweedie distribution to standardize the CPUE and to estimate relative abundance indices based on the Indonesian longline dataset time series. Data were collected from January 2006 to October 2015 (106 trip observer and 8.989 fishing days) by conducting direct onboard observation on tuna longline vessels operating in the Indian Ocean. The result show that year, area,hooks between floats, year*season, year*area and year* hooks between floats significantly influenced the nominal CPUE of albacore. The highest value of Standardized CPUE appeared in 2014 and probably related to the large number of foreign fishing vessels with a high capacity (over 60 GT) targeting frozen tuna including albacore. In 2015, standardized CPUE value was sharply decreased due to the ban of foreign vessels in Indonesia. 

scholarly journals Characteristics Fishing Areas of Bigeye Tuna (Thunnus Obesus) in Depth of 155 m Based on Remotely Sensed Data

2020 ◽  
Vol 5 (1) ◽  
pp. 62-70
Author(s):  
Achmad Fachruddin-Syah ◽  
Jonson Lumban Gaol ◽  
Mukti Zainuddin ◽  
Nadela Rista Apriliya ◽  
Dessy Berlianty ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Remotely Sensed ◽  
Eastern Indian Ocean ◽  
Bigeye Tuna ◽  
Remotely Sensed Data ◽  
Surface Salinity ◽  
Chl A ◽  
Fishing Vessels ◽  
Thunnus Obesus ◽  
Daily Data

Bigeye tuna (Thunnus obesus) is one of the commercially important pelagic species that caught mostly in the eastern Indian Ocean. This species prefers to stay close, and is usually below the thermocline layer. Remotely sensed data was used to determine the characteristics of Bigeye tuna fishing areas at a depth of 155 meter. Fishing vessels for Bigeye tuna were obtained from vessel monitoring systems (VMS) from January through December, 2015-2016. Daily data on sub-surface temperature (SST), sub-surface chlorophyll-a concentration (SSC), and sub-surface salinity (SSS) were obtained from the INDESO Project website. All oceanographic parameter data were selected at a depth of 155 m. The position of Bigeye tuna and oceanographic data were then grouped into 2 group monsoon, southeast monsoon (April – September) and northwest monsoon (October – March). The results showed that, during the southeast and northwest monsoon, Bigeye tuna mostly found in SSC of 0.03 – 0.05 mg/m3, SST of 16° - 18°C and salinity of 34 psu. These results showed that at depth of 155 m, Bigeye Tuna prefers to stay in small chl-a (0.03 – 0.04 mg/m3), low SST (16° - 18°C) and salinity of 34 psu. These information were essential and could be used to support fisheries management decisions especially for Bigeye Tuna in the eastern Indian Ocean.

scholarly journals Reproductive Biology of Albacore Tuna (Thunnus alalunga) in the Western Indian Ocean

PLoS ONE ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. e0168605 ◽  
Author(s):  
Zahirah Dhurmeea ◽  
Iker Zudaire ◽  
Emmanuel Chassot ◽  
Maria Cedras ◽  
Natacha Nikolic ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Reproductive Biology ◽  
Western Indian Ocean ◽  
Albacore Tuna ◽  
Thunnus Alalunga

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 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 Spatial Distribution, Behaviour, and Biological Aspect of Albacore (Thunnus alalunga) Caught in Eastern Indian Ocean

2017 ◽  
Vol 22 (3) ◽  
pp. 111
Author(s):  
Fathur Rochman ◽  
Irwan Jatmiko ◽  
Bram Setyadji
Keyword(s):  
Indian Ocean ◽  
Eastern Indian Ocean ◽  
Allometric Growth ◽  
Biological Aspect ◽  
Weight Relationship ◽  
Feeding Periodicity ◽  
Thunnus Alalunga ◽  
Tuna Fisheries ◽  
June July ◽  
Distribution Behaviour

This study highlighted the occurrence of the Indonesian tuna longline fishery targeting albacore (Thunnus alalunga) caught in the Eastern Indian ocean. The data used in this study based on the Research Institute for Tuna Fisheries (RITF) observer program in Benoa. This paper presents the current information on biological aspect (size distribution and length-weight relationship) and fish behavior (swimming layer and feeding periodicity) of albacore. Total albacore samples of  3,152 were taken from scientific observer data from 2010-2013. The study area of albacore was between 0-33°S and 75-131°E. Albacore length  distributed from 70-196 cmFL (median=93 cmFL, mode=100 cmFL, mean=92.12 cmFL) and dominated at size of 95 cmFL. The highest percentage length of albacore was  >90 cm (L50) occured in the area between (30-35°S and 80-95°E) and (10-15°S and 120-125°E). The length weight relationship was determined to be W=0.0045 FL1.8211  (W in kg, FL in cm). The expected season to catch the ALB was from April to July with the peak season in June and July. The swimming layer of albacore based on minilogger data were distributed from at 118 to 341 m depth and mostly catch at depth of 156 m with temperature degree 18°C.  The feeding periodicity of albacore’s are start from 7:45am to 17:59 pm, mostly active at 10 am to 11 am. The majority of ALB caught by Indonesian longliner was mature condition and negative allometric growth. The ALB peak season was in June-July and the best time to catch was 10 am to 11 am at depth of 156 m. Keywords : albacore, feeding periodicity, swimming layer,  CPUE

scholarly journals Spatial variation in stable isotopes and fatty acid trophic markers in albacore tuna (Thunnus alalunga) from the western Indian Ocean

2020 ◽  
Vol 161 ◽  
pp. 103286
Author(s):  
Zahirah Dhurmeea ◽  
Heidi Pethybridge ◽  
Clothilde Langlais ◽  
Christopher J. Somes ◽  
Natacha Nikolic ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Fatty Acid ◽  
Indian Ocean ◽  
Spatial Variation ◽  
Western Indian Ocean ◽  
Albacore Tuna ◽  
Thunnus Alalunga ◽  
Trophic Markers
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