scholarly journals In situacoustic target-strength measurement of bigeye (Thunnus obesus) and yellowfin tuna (Thunnus albacares) by coupling split-beam echosounder observations and sonic tracking

1999 ◽  
Vol 56 (1) ◽  
pp. 51-60 ◽  
Author(s):  
A Bertrand
2009 ◽  
Vol 1 (1) ◽  
Author(s):  
Henry M. Manik

A preliminary research programme was carried out in order to study the acoustic wave reflection or target strength (TS) of tuna fish using a quantitative echo sounder (QES). The relationships between TS to fork length (FL) and swimbladder volume, for bigeye tuna (Thunnus obesus) and yellowfin tuna (T. albacares) are investigated. The TS of bigeye tuna was about 3 dB higher than yellowfin tuna when comparing species at the same size. The result can be correlated to the swimbladder volume differencebetween species. The relationship between TS and swimbladder volume was quantified for both species.Keywords: tuna fish, target strength, quantitative echo sounder


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.


2011 ◽  
Vol 77 (6) ◽  
pp. 903-913 ◽  
Author(s):  
Hsueh-Jung Lu ◽  
Myounghee Kang ◽  
Hsing-Han Huang ◽  
Chi-Chang Lai ◽  
Long-Jin Wu

2002 ◽  
Vol 59 (6) ◽  
pp. 1002-1013 ◽  
Author(s):  
Arnaud Bertrand ◽  
Erwan Josse ◽  
Pascal Bach ◽  
Philippe Gros ◽  
Laurent Dagorn

We studied relationships between tropical tunas (albacore (Thunnus alalunga), bigeye (Thunnus obesus), and yellowfin (Thunnus albacares)) and their biotic and abiotic environments through simultaneous acoustic observations of tunas and their prey, experimental longline catch, and oceanographic data in French Polynesia. Vertical habitat limits were estimated based on temperature and dissolved oxygen at capture data. We then studied tuna-micronekton relationships to better understand how tuna occupy the pelagic space. At a regional scale, tunas were more abundant in areas rich in prey with favourable hydrological conditions. Inside such areas, at the scale of a longline set, however, the longline catches were maximal only when prey were not distributed in dense patches (except for yellowfin tuna). We interpreted this result by considering that areas with high prey abundance attract tunas, but at a small scale, if prey are patchy distributed, tunas are more inclined to feed on them rather than on longline baits. The effect of patches on yellowfin tuna catch per unit effort (CPUE) does not appear likely because this species also feeds on the mixed layer, where patch density was very low. Not only hydrological characteristics, but also prey density and prey patch characteristics, should be taken into account for interpreting longline CPUE data.


Sign in / Sign up

Export Citation Format

Share Document