Abstract
The Yellowfin Tuna Thunnus albacares is one of the major fish species caught around subsurface fish aggregation devices (FADs) in the waters southwest of Taiwan. However, how it interacts with other organisms around FADs is poorly known. In this study, the diet and feeding habits of juvenile Yellowfin Tuna were estimated from the analysis of stomach contents from 1,477 specimens with FLs ranging from 24 to 108 cm and stable isotope analysis (202 specimens) collected around FADs in the waters southwest of Taiwan. The analysis of stomach contents indicated that juvenile Yellowfin Tuna with FL < 50 cm mainly feed on larval purpleback flying squid Sthenoteuthis oualaniensis, larval shrimps, and zooplanktonic organisms such as amphipods. Yellowfin Tuna with FL of ∼50 cm switch their diet to teleost fishes such as Japanese Barracudina Lestrolepis japonica, Skinnycheek Lanternfish Benthosema pterotum, and fishes in the families Exocoetidae and Scombridae. Stable isotope analysis indicated that the δ15N values ranged between 6.2‰ and 12.6‰, and the estimated trophic position varied from 3.18 ± 0.24 for tuna with FL < 30 cm, while it reached 4.59 ± 0.50 for those with FL > 50 cm and 4.75 ± 0.06 for those with FL > 90 cm. Based on the distinct diet shift of the juvenile Yellowfin Tuna, demonstrated by both stomach contents and stable isotope analyses, this study concluded that the tuna shift their diet at approximately 50 cm FL.
Received March 31, 2015; accepted September 9, 2015
You have requested "on-the-fly" machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Show full disclaimer
Neither ProQuest nor its licensors make any representations or warranties with respect to the translations. The translations are automatically generated "AS IS" and "AS AVAILABLE" and are not retained in our systems. PROQUEST AND ITS LICENSORS SPECIFICALLY DISCLAIM ANY AND ALL EXPRESS OR IMPLIED WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES FOR AVAILABILITY, ACCURACY, TIMELINESS, COMPLETENESS, NON-INFRINGMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Your use of the translations is subject to all use restrictions contained in your Electronic Products License Agreement and by using the translation functionality you agree to forgo any and all claims against ProQuest or its licensors for your use of the translation functionality and any output derived there from. Hide full disclaimer
Details
1 Executive Yuan, Council of Agriculture, Fisheries Research Institute, Coastal and Offshore Resources Research Center, Kaohsiung 80627, Taiwan; and Department of Environmental Biology and Fisheries Science, National Taiwan Ocean University, Keelung, Taiwan
2 Department of Environmental Biology and Fisheries Science, National Taiwan Ocean University, Keelung, Taiwan
3 Institute of Marine Affairs and Resource Management, National Taiwan Ocean University, Keelung 20224, Taiwan; and George Chen Shark Research Center, National Taiwan Ocean University, Keelung, Taiwan
4 Executive Yuan, Council of Agriculture, Fisheries Research Institute, Coastal and Offshore Resources Research Center, Kaohsiung, Taiwan