scholarly journals Movement behaviour of skipjack (Katsuwonus pelamis) and yellowfin (Thunnus albacares) tuna at anchored fish aggregating devices (FADs) in the Maldives, investigated by acoustic telemetry

2012 ◽  
Vol 26 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Rodney Govinden ◽  
Riyaz Jauhary ◽  
John Filmalter ◽  
Fabien Forget ◽  
Marc Soria ◽  
...  
2020 ◽  
Vol 26 (2) ◽  
pp. 83
Author(s):  
Agustinus Anung Widodo ◽  
Wudianto Wudianto ◽  
Lilis Sadiyah ◽  
Mahiswara Mahiswara ◽  
Craig Proctor ◽  
...  

The use of anchored fish aggregating devices (a-FADs) in the Indonesia-Indian Ocean has increased rapidly. Since 2004, the Government of Indonesia has issued various FAD related fisheries regulations; however, its implementation was difficult, largely due to the lack of such information. As an endeavor to improve the management of tuna fisheries associated with FADs in this area, an Indonesia–Australia research collaboration project conducted a port sampling program from November 2013 to December 2015 in three key fishing ports in the western Indonesia, i.e., Pelabuhanratu (West Jawa), Muara Padang (West Sumatera), and Bungus (West Sumatera). Data were collected through daily enumeration and interviews with skippers, which consisted of catch, trip duration, biological data, and number of FADs visited. These data were analyzed to estimate catch rate, success rate, and length frequency distribution. The success rate of hand line/trolling line (HL/TR) at Muara Padang showed much lower than that at Pelabuhanratu. This may be due to more a-FADs or higher density in the Padang region, competing with purse seine (PS) boats operating in the same area, than those in the Pelabuhanratu region. The species composition caught by HL/TR and PS associated a-FADs in Indonesian FMA 572 and 573 include skipjack (SKJ, Katsuwonus pelamis), yellowfin (YFT, Thunnus albacares) and bigeye tuna (BET, T. obesus). A large proportion of the SKJ, YFT and BET caught at both Indonesian FMA 572 and 573 were juvenile fish, below the reported length at maturity (Lm) for those species.


2014 ◽  
Vol 71 (7) ◽  
pp. 1774-1780 ◽  
Author(s):  
Daniel W. Fuller ◽  
Kurt M. Schaefer

Abstract Experiments were conducted to evaluate a fishing captain's ability to predict species composition, sizes, and quantities of tunas associated with drifting fish-aggregating devices (FADs), before encirclement with a purse-seine net. Operating in the equatorial eastern Pacific Ocean, during 11 May–23 July 2011, Captain Ricardo Diaz detected small quantities of bigeye (Thunnus obesus) and yellowfin (Thunnus albacares) tunas within large FAD-associated aggregations dominated by skipjack tuna (Katsuwonus pelamis). The captain's predictions were significantly related to the actual total catch and catch by species, but not to size categories by species. His predictions of species composition were most accurate when estimates of bigeye and yellowfin tuna were combined. If purse-seine captains are able to make accurate predictions of the proportion of bigeye and yellowfin tunas present in mixed-species aggregations associated with FADs, managers may wish to consider incentives to fishers to reduce the fishing mortality on those species.


1999 ◽  
Vol 202 (16) ◽  
pp. 2127-2138 ◽  
Author(s):  
T. Knower ◽  
R.E. Shadwick ◽  
S.L. Katz ◽  
J.B. Graham ◽  
C.S. Wardle

To learn about muscle function in two species of tuna (yellowfin Thunnus albacares and skipjack Katsuwonus pelamis), a series of electromyogram (EMG) electrodes was implanted down the length of the body in the internal red (aerobic) muscle. Additionally, a buckle force transducer was fitted around the deep caudal tendons on the same side of the peduncle as the electrodes. Recordings of muscle activity and caudal tendon forces were made while the fish swam over a range of steady, sustainable cruising speeds in a large water tunnel treadmill. In both species, the onset of red muscle activation proceeds sequentially in a rostro-caudal direction, while the offset (or deactivation) is nearly simultaneous at all sites, so that EMG burst duration decreases towards the tail. Muscle duty cycle at each location remains a constant proportion of the tailbeat period (T), independent of swimming speed, and peak force is registered in the tail tendons just as all ipsilateral muscle deactivates. Mean duty cycles in skipjack are longer than those in yellowfin. In yellowfin red muscle, there is complete segregation of contralateral activity, while in skipjack there is slight overlap. In both species, all internal red muscle on one side is active simultaneously for part of each cycle, lasting 0.18T in yellowfin and 0.11T in skipjack. (Across the distance encompassing the majority of the red muscle mass, 0.35-0.65L, where L is fork length, the duration is 0.25T in both species.) When red muscle activation patterns were compared across a variety of fish species, it became apparent that the EMG patterns grade in a progression that parallels the kinematic spectrum of swimming modes from anguilliform to thunniform. The tuna EMG pattern, underlying the thunniform swimming mode, culminates this progression, exhibiting an activation pattern at the extreme opposite end of the spectrum from the anguilliform mode.


2002 ◽  
Vol 62 (3) ◽  
pp. 453-457 ◽  
Author(s):  
B. M. M. FERNANDES ◽  
A. KOHN ◽  
A. L. SANTOS

Rhipidocotyle pentagonum (Ozaki, 1924) is reported for the first time in South America parasitizing Auxis thazard and in a new host Katsuwonus pelamis. Tergestia laticollis (Rudolphi, 1819) is reported for the first time in South America and in Thunnus albacares, representing a new host record. Copiatestes filiferus (Leuckart, in Sars, 1885) is recorded for the first time in Brazil and in Thunnus albacares, another new host record. Tetrochetus coryphaenae (Yamaguti, 1934) is presented for the first time in Brazil parasitizing Thunnus albacares.


Author(s):  
Colombo Estupiñán-Montaño ◽  
Fabian Pacheco-Triviño ◽  
Luis G. Cedeño-Figueroa ◽  
Felipe Galván-Magaña ◽  
Jose F. Estupiñán-Ortiz

We analysed the stomach contents of 69 silky sharks Carcharhinus falciformis, 44 blacktip sharks Carcharhinus limbatus and 24 whitenose sharks Nasolamia velox caught in the Ecuadorian Pacific from August 2003 to December 2004. Prey included bony fishes, elasmobranchs, molluscs, crustaceans and turtles, with bony fishes being the most important to the diets of all three sharks, suggesting they are piscivorous predators. Based on the index of relative importance, the C. falciformis diet includes Thunnus albacares, Thunnus sp. and Auxis thazard, as well as some squid, fish and turtles. Similarly, the C. limbatus diet was dominated by T. albacares, Exocoetus monocirrhus, A. thazard, Katsuwonus pelamis, members of the Ophichthidae family and other elasmobranchs. Meanwhile, N. velox consumed mainly Dosidicus gigas, Larimus argenteus, Cynoscion sp. and Lophiodes spilurus. There is little competition for food between these tertiary carnivores: C. limbatus prefers prey from coastal-oceanic habitats; C. falciformis consumes mostly oceanic prey and N. velox focuses on prey from coastal habitats. The lack of information on the biology of sharks in Ecuador hinders the development of appropriate management and conservation plans to protect shark resources. This study increases our knowledge and understanding of sharks in Ecuador, thus contributing to their conservation.


2017 ◽  
Vol 14 (3) ◽  
pp. 313 ◽  
Author(s):  
Budi Nugraha ◽  
Enjah Rahmat

Tulisan ini menyajikan tentang status perikanan huhate di Bitung meliputi deskripsi unit penangkapan, daerah penangkapan, komposisi hasil tangkapan, catch per unit of effort, dan ukuran ikan pertama kali tertangkap. Data dikumpulkan selama tahun 2004 sampai dengan 2005. Hasil penelitian menunjukkan bahwa huhate yang terdapat di Bitung dioperasikan dengan kapal penangkapan yang terbuat dari kayu berukuran 50 sampai dengan 80 GT. Daerah penangkapan di sekitar lokasi rumpon di Laut Sulawesi dan Laut Maluku. Hasil tangkapan yang diperoleh terdiri atas cakalang (Katsuwonus pelamis), madidihang (Thunnus albacares), baby tuna (Thunnus spp.), dan tongkol (Auxis spp.) serta hasil tangkapan sampingan yaitu lemadang (Coryphaena hippurus) dan sunglir (Elagatis bipinnulatus). Hasil analisis catch per unit of effort diperoleh bahwa nilai catch per unit of effort baby tuna (Thunnus spp.) mengalami kenaikan pada bulan Agustus 2004, dan cakalang (Katsuwonus pelamis) mengalami kenaikan pada bulan September 2004. Hasil analisis terhadap ukuran pertama kali cakalang (Katsuwonus pelamis) tertangkap oleh huhate 49,3 FLcm. Ukuran ini lebih panjang dibandingkan ukuran pertama kali cakalang (Katsuwonus pelamis) matang gonad. Sedangkan hasil analisis terhadap ukuran pertama kali madidihang (Thunnus albacares) tertangkap oleh huhate 51,6 FLcm. Ukuran ini lebih pendek dibandingkan ukuran pertama kali madidihang (Thunnus albacares) matang gonad. This paper presents the status of pole and line fishery in Bitung of North Sulawesi, consisting of description of fishing gear, fishing ground, catch composition, catch per unit of effort, and length at first capture. Data were collected during the period of 2004 until 2005. Results show that the pole and line in Bitung operated by wooden vessels of 50 until 80 GT. The fishing grounds were the waters around FADs location in Sulawesi Sea and Maluku Sea. Catch composition consists of skipjack tuna (Katsuwonus pelamis), yellow fin tuna (Thunnus albacares), baby tuna (Thunnus spp.), and frigate tuna (Auxis spp.), while the bycatch consisted of dolphinfish (Coryphaena hippurus) and rainbow runner (Elagatis bipinnulatus). Catch per unit of effort analysis shows that catch per unit of effort value of baby tuna (Thunnus spp.) increased on August 2004, whereas catch per unit of effort value of skipjack tuna (Katsuwonus pelamis) increased on September 2004. The length at first capture of skipjack tuna (Katsuwonus pelamis) was 49,3 FLcm. The catch size was bigger than the length at first maturity for skipjack tuna (Katsuwonus pelamis). The length at first capture of yellowfin tuna (Thunnus albacares) was 51,6 FLcm. This catch size was smaller than the length at first maturity for yellowfin tuna (Thunnus albacares).


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.


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