scholarly journals Genomic analysis reveals multiple mismatches between biological and management units in yellowfin tuna (Thunnus albacares)

2018 ◽  
Vol 75 (6) ◽  
pp. 2145-2152 ◽  
Author(s):  
Rachel B Mullins ◽  
Niall J McKeown ◽  
Warwick H H Sauer ◽  
Paul W Shaw
Keyword(s):  
Indian Ocean ◽  
Genomic Analysis ◽  
Yellowfin Tuna ◽  
Thunnus Albacares ◽  
Management Units ◽  
Spawning Site ◽  
Asymmetric Dispersal ◽  
Outlier Loci ◽  
The Indian Ocean ◽  
Mixed Stock

Abstract The South African (SAF) yellowfin tuna (Thunnus albacares) fishery represents a potential example of misalignment between management units and biological processes. The SAF fishery spans an operational stock with a boundary at 20°E, either side of which fish are considered part of Atlantic or Indian Ocean regional stocks. However, the actual recruitment of fish from Atlantic and Indian Ocean spawning populations into SAF waters is unknown. To address this knowledge gap, genomic analysis (11 101 SNPs) was performed on samples from Atlantic and Indian Ocean spawning sites, including SAF sites spanning the current stock boundary. Outlier loci conferred high discriminatory power to assignment tests and revealed that all SAF fish were assigned to the Indian Ocean population and that no Atlantic Ocean fish appeared in the SAF samples. Additionally, several Indian Ocean migrants were detected at the Atlantic spawning site demonstrating asymmetric dispersal and the occurrence of a mixed-stock fishery in Atlantic waters. This study highlights both the spatial inaccuracy of current stock designations and a misunderstanding of interactions between the underlying biological units, which must be addressed in light of local and global declines of the species. Specifically, the entire SAF fishery must be managed as part of the Indian Ocean stock.

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

2019 ◽  
Vol 11 (3) ◽  
pp. 161
Author(s):  
Maya Agustina ◽  
Bram Setyadji ◽  
Prawira Atmaja Rintar Pandapotan Tampubolon
Keyword(s):  
Indian Ocean ◽  
Size Structure ◽  
Landing Site ◽  
Yellowfin Tuna ◽  
Fishing Gear ◽  
Thunnus Albacares ◽  
Skipjack Tuna ◽  
The Indian Ocean ◽  
Average Size ◽  
Relationship Of

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.

scholarly journals Otolith microchemistry: a useful tool for investigating stock structure of yellowfin tuna (Thunnus albacares) in the Indian Ocean

2019 ◽  
Vol 70 (12) ◽  
pp. 1708 ◽  
Author(s):  
Iraide Artetxe-Arrate ◽  
Igaratza Fraile ◽  
David A. Crook ◽  
Iker Zudaire ◽  
Haritz Arrizabalaga ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Indian Ocean ◽  
Yellowfin Tuna ◽  
Thunnus Albacares ◽  
Stock Structure ◽  
North West ◽  
Natal Origin ◽  
Oxygen Stable Isotopes ◽  
West Indian Ocean ◽  
The Indian Ocean

A better understanding of the stock structure of yellowfin tuna (Thunnus albacares) in the Indian Ocean is needed to ensure the sustainable management of the fishery. In this study, carbon and oxygen stable isotopes (δ13C and δ18O) and trace elements (138Ba, 55Mn, 25Mg and 88Sr) were measured in otoliths of young-of-the-year (YOY) and age-1 yellowfin tuna collected from the Mozambique Channel and north-west Indian Ocean regions. Elemental profiles showed variation in Ba, Mg and Mn in YOY otolith composition, but only Mn profiles differed between regions. Differences in YOY near-core chemistry were used for natal-origin investigation. Ba, Mg and Mn were sufficiently different to discriminate individuals from the two regions, in contrast with carbon and oxygen stable isotopes. A linear discriminant analysis resulted in 80% correct classification of yellowfin tuna to their natal origin. Classification success increased to 91% using a random forest algorithm. Finally, a unique larval source was detected among age-1 yellowfin tuna. The signal of these fish resembled that of YOY from a north-west Indian Ocean origin, highlighting the importance of local production. The present study supports the use of otolith chemistry as a promising approach to analyse yellowfin stock structure in the Indian Ocean.

scholarly journals Mercury and cadmium distribution in yellowfin tuna (Thunnus albacares) from two fishing grounds in the Indian Ocean near Sri Lanka

Heliyon ◽  
2019 ◽  
Vol 5 (6) ◽  
pp. e01875 ◽  
Author(s):  
B.K.K.K. Jinadasa ◽  
G.S. Chathurika ◽  
G.D.T.M. Jayasinghe ◽  
C.D. Jayaweera
Keyword(s):  
Sri Lanka ◽  
Indian Ocean ◽  
Yellowfin Tuna ◽  
Thunnus Albacares ◽  
The Indian Ocean

scholarly journals Otolith δ18O Composition as a Tracer of Yellowfin Tuna (Thunnus albacares) Origin in the Indian Ocean

Oceans ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 461-476
Author(s):  
Iraide Artetxe-Arrate ◽  
Igaratza Fraile ◽  
Jessica Farley ◽  
Audrey M. Darnaude ◽  
Naomi Clear ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Secondary Ion Mass Spectrometry ◽  
Multinomial Logistic Regression ◽  
Adult Population ◽  
Equatorial Indian Ocean ◽  
Isotopic Signature ◽  
Yellowfin Tuna ◽  
Thunnus Albacares ◽  
The Indian Ocean ◽  
A Minor

Yellowfin tuna of the Indian Ocean is overfished, and a better understanding of the stock structure is needed to enable sustainable management. Here, otolith δ18O values of young-of-the-year fish from known nursery areas of the equatorial Indian Ocean (West, Central and East) were used to establish a reference isotopic signature to predict the origin of sub-adult and adult individuals. Sub-adult tuna otolith δ18O values from Reunion Island were similar to the West nursery signature, but otolith δ18O values of sub-adults from Pakistan were unlike any of the nurseries sampled. Therefore, δ18O values from the Pakistan area samples were considered an additional nursery source for predicting the origin of adult tuna, using a multinomial logistic regression classification method. The western equatorial area was the most productive nursery for three fishing grounds sampled, with a minor contribution of Pakistan-like origin fish. Contribution of Central or East nurseries to the adult population was negligible. One adult otolith was analysed by secondary ion mass spectrometry along the otolith growth transect and results were compared with an isoscape approach to infer lifetime movements. This study is an important first step towards understanding the spatial structure and connectivity of the species.

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 Population Dynamics of Yellowfin Tuna Thunnus albacares (Bonnaterre, 1788) in the Fisheries Management Area 573 of the Indian Ocean

2021 ◽  
Vol 79 (2) ◽  
pp. 53-60
Author(s):  
Abdul Ghofar ◽  
Suradi W. Saputra ◽  
Agus Sabdono ◽  
Anhar Solichin ◽  
Wiwiet T. Taufani ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Mortality Rate ◽  
Indian Ocean ◽  
Fisheries Management ◽  
Yellowfin Tuna ◽  
Growth Equation ◽  
Thunnus Albacares ◽  
Total Production ◽  
Management Area ◽  
The Indian Ocean

Abstract Yellowfin tuna Thunnus albacares is one of the major species of tuna caught in the Fisheries Management Area (FMA) 573 of the Indian Ocean. Its production contributed to 35.83% of the total production of tuna in 2013. The study was conducted to assess the population dynamics of this species in FMA 573, based on length-frequency data collected in 2013-2017, and was analysed using FiSAT II software. The results obtained show length-weight relationship of W = 0.000052 FL2.78, negative allometric growth and growth equation of Lt = 194.25 (1-e-0.51 (t + 0.1889)). The length at first capture was estimated at 140 cm FL. Recruitment season occurs between July and September, with a peak in August. The rate of total mortality (Z) was 2.32 yr-1, including natural mortality rate (M) of 0.69 yr-1 and fishing mortality rate (F) of 1.63 yr-1. The exploitation rates of yellowfin tuna were estimated to be 0.70, indicating that it has exceeded the optimum exploitation rate (E = 0.5) and that overexploitation had occurred. There is an obvious need for consistent monitoring and surveillance of fishing fleet, type and size of fishing gear, as well as the fish size and quantity of the catch.

Climatic oscillations effect on the yellowfin tuna ( Thunnus albacares ) Spanish captures in the Indian Ocean

2020 ◽  
Vol 29 (6) ◽  
pp. 572-583
Author(s):  
José Carlos Báez ◽  
Ivone A. Czerwinski ◽  
María Lourdes Ramos
Keyword(s):  
Indian Ocean ◽  
Yellowfin Tuna ◽  
Thunnus Albacares ◽  
Climatic Oscillations ◽  
The Indian Ocean
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