Diet composition of bigeye tuna ( Thunnus obesus ) and yellowfin tuna ( Thunnus albacares ) caught on aggregated schools in the western equatorial Atlantic Ocean

2019 ◽  
Vol 35 (5) ◽  
pp. 1111-1118 ◽  
Author(s):  
Guelson Batista Silva ◽  
Humberto Gomes Hazin ◽  
Fabio Hissa Vieira Hazin ◽  
Teodoro Vaske‐Jr
2011 ◽  
Vol 68 (6) ◽  
pp. 1063-1071 ◽  
Author(s):  
Kuo-Wei Lan ◽  
Ming-An Lee ◽  
Hsueh-Jung Lu ◽  
Wei-Juan Shieh ◽  
Wei-Kuan Lin ◽  
...  

Abstract Lan, K-W., Lee, M-A., Lu, H-J., Shieh, W-J., Lin, W-K., and Kao, S-C. 2011. Ocean variations associated with fishing conditions for yellowfin tuna (Thunnus albacares) in the equatorial Atlantic Ocean. – ICES Journal of Marine Science, 68: 1063–1071. In this study, the Taiwanese longline (LL) fishery data were divided into two types: regular LL and deep LL. Furthermore, we collected environmental variables, such as sea surface temperature (SST), subsurface temperature, chlorophyll a concentration, net primary productivity, windspeed, and the north tropical Atlantic SST index (NTA) during the period 1998–2007 to investigate the relationship between LL catch data and oceanic environmental factors using principal component analysis (PCA). After the daily LL was separated into two types of LL, the results indicated that the deep LL was the major fishery catching yellowfin tuna (YFT) in the equatorial Atlantic Ocean. In 2003–2005, especially in 2005, the monthly catch by deep LL was double those of other years. The spatial distribution of the nominal catch per unit effort (cpue) by deep LL showed the maximum aggregation of YFT in waters with temperature above 24–25°C. The YFT mainly aggregated in the equatorial Atlantic, extending east in the first and second quarters of the year. In the third quarter of the year, the SST decreased off West Africa and the YFT migrated westwards to 15°W. Results of PCA indicated that higher subsurface water temperatures resulted in a deeper thermocline and caused a higher cpue of YFT, but the influence of NTA on the cpue of YFT seemed to be insignificant.


2017 ◽  
Vol 3 (6) ◽  
pp. 377
Author(s):  
Ria Faizah ◽  
Aisayah Aisayah

Sendang Biru merupakan salah satu tempat pendaratan ikan pelagis besar di Jawa Timur. Penelitian tentang komposisi jenis dan ukuran ikan pelagis besar hasil tangkapan pancing ulur yang didaratkan di PPI Pondok Dadap, Sendang Biru, Jawa Timur, dilakukan pada bulanApril dan Oktober 2010. Hasil penelitian menunjukkan hasil tangkapan pancing ulur didominasi oleh jenis tuna (Thunnus albacares dan Thunnus obesus) 45%, cakalang (Katsuwonus pelamis) sebesar 38 %, dan lainnya (marlin, lemadang, lauro) sebesar 1,7 %. Ikan tuna yang didaratkan terdiri dari jenis yellowfin tuna (Thunnus albacares) dan bigeye tuna (T. obesus) dengan ukuran panjang cagakmasing –masing berkisar antara 40 - 170 cmFL dan 40 - 140 cmFL. Berat individumasing-masing berkisar antara 0.1 - 71 kg dan 0.5 - 43 kg. Sendang Biru is one of big pelagic’s landing site in East Java. Tuna on this research are caught by handline that landing in PPI Pondok Dadap, Sendang Biru, East Java. Research on the species composition and size distribution of big pelagic fish caught by handline were carried out during April and October 2010 at Sendang Biru, East Java. The result showed that Thunnus sp. are the most landed (45%) followed by Katsuwonus pelamis (38 %) and others (Xiphias gladius, Coriphaena sp., Elagatis bipinnulatus) of 1.7 %. The dominant fork lengthof Thunnus albacares and Thunnus obesus ranged from about 40 - 170 cm and 40 – 140 cm. Individual weight ranged between 0.1 - 71 kg and 0.5 - 43 kg respectivelly.


2020 ◽  
Vol 77 (4) ◽  
pp. 637-643 ◽  
Author(s):  
Allen H. Andrews ◽  
Ashley Pacicco ◽  
Robert Allman ◽  
Brett J. Falterman ◽  
Erik T. Lang ◽  
...  

Estimates of age and growth of yellowfin (Thunnus albacares) and bigeye (Thunnus obesus) tuna remain problematic because validation of growth zone deposition (opaque and translucent) has not been properly evaluated. Otolith growth structure (zone clarity) can be poorly defined for tropical tunas, but the use of bomb radiocarbon dating has validated age estimates to 16–18 years for yellowfin and bigeye tuna. Use of the radiocarbon decline period — defined by regional coral and otoliths — provided valid ages through ontogeny. Yellowfin tuna aged 2–18 years (n = 34, 1029–1810 mm FL) and bigeye tuna aged 3–17 years (n = 12, 1280–1750 mm FL) led to birth years that were coincident with the bomb radiocarbon decline. The results indicate there was no age reading bias for yellowfin tuna and that age estimates of previous studies were likely underestimated for both species.


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