کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5765419 1626776 2017 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Feeding habits of juvenile yellowfin tuna (Thunnus albacares) in Ecuadorian waters assessed from stomach content and stable isotope analysis
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک علوم آبزیان
پیش نمایش صفحه اول مقاله
Feeding habits of juvenile yellowfin tuna (Thunnus albacares) in Ecuadorian waters assessed from stomach content and stable isotope analysis
چکیده انگلیسی
Size-related shifts in feeding habits of juvenile yellowfin tuna (YFT), Thunnus albacares (Bonnaterre, 1788), in Ecuadorian waters were assessed using stomach content analysis (SCA) (n = 339) and stable isotope analysis (n = 83). In all size classes, fishes were the predominant prey group in the diet (Alimentary Index, %AI = 96.86) followed by cephalopods (%AI = 3.29) and crustaceans (%AI = 0.03). PERMANOVA analysis revealed significant variations in diet with body size: i) Class I YFT (≤50 cm in fork length, FL) fed mainly on laternfishes, family Myctophidae (%AI = 37.34), and jumbo squid, Dosidicus gigas (%AI = 36.06), Class II YFT (50-60 cm, FL) consumed bullet and frigate tunas, Auxis spp., unidentifiable fish and jumbo squid (%AI = 47.75, %AI = 25.06 and%AI = 21.67, respectively), and Class III YFT (≥ 60 cm, FL) preyed almost exclusively on bullet and frigate tunas (%AI = 90.85). Mean ± SD muscle isotope values were 12.14 ± 1.95‰ for δ15N and −17.42 ± 0.27 for δ13C‰; mean (±SD) liver values were 11.30‰ for δ15N and −17.42 ± 0.27‰ for δ13C. Overall, liver and muscle samples showed significant size-related differences in δ15N and δ13C. Stable isotope Bayesian ellipses, SEAc, did not show trophic overlap among size classes. A significant positive linear correlation was observed between δ15N and δ13C measured in liver and muscle tissues with body size, suggesting an increase of prey size as tuna grew. These results indicate that the observed size-related diet shifts are not only related to prey type, but also to prey size.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Fisheries Research - Volume 194, October 2017, Pages 89-98
نویسندگان
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