Investigation of trophic level and niche partitioning of 7 cetacean species by stable isotopes, and cadmium and arsenic tissue concentrations in the western Pacific Ocean

Annual variability in dentin δ15N and δ13C reveal sex differences in weaning age and feeding habits in Risso's dolphins (Grampus griseus)

“…In addition, lower δ 15 N values in adult males were previously attributed to consumption of deep‐sea cephalopods of high cadmium concentrations (Liu et al . ). Together, these suggest that the observed sex difference in isotopic ratios could also be due to differences in isotopic discrimination between sexes related to their physiological states ( e.g ., growth and reproduction), even when diets are the same, as has been observed in captive bottlenose dolphins (Browning et al .…”

“…Lower δ 15 N values (12.21‰ ± 0.26‰, n = 3) in adult males (TBL > 270 cm) than in immature individuals (TBL < 200 cm) from both sexes (13.27‰ ± 0.24‰, n = 5) was attributed to consumption of deep‐sea cephalopods of high cadmium concentrations in the former (Liu et al . ), suggesting possible differences in diet among age groups. Teeth archived in Taiwan provided an opportunity to examine age‐specific variations in isotope ratios of individual Risso's dolphins and to determine ontogenetic patterns of diet shifts.…”

Resource partitioning among sympatric elasmobranchs in the central-western Mediterranean continental shelf

“…Unfortunately, most of the literature on trophic interactions, especially in the Mediterranean, usually focuses on the diet comparison of just two or three species (Valls et al 2011(Valls et al , 2017Barría et al 2015Barría et al , 2018. More complex studies are limited to a few papers, published in recent decades and focusing on the main predator groups, like bony fishes (Cabral et al 2002;Valls et al 2014b;Karachle 2017;Park et al 2017;Paul et al 2018), elasmobranchs (Orlov 1998;Valls et al 2011; Barría et al 2015Barría et al , 2018Kousteni et al 2018), cetaceans (Liu et al 2015) and cephalopods (Cherel et al 2009), while studies on betweentaxa interactions are even fewer (Valls et al 2014a(Valls et al , 2017. Concentration on large predator groups is driven by the predators roles in the food chain, i.e.…”

Concordance between genetic diversity and marine biogeography in a highly mobile marine mammal, the Risso's dolphin

“…Given the distinct physical, chemical and ecological features but large geographical area represented by these three provinces, resource specialization may be especially relevant in this case. Risso's dolphins feed primarily on cephalopod prey in all regions (Baird, ), however, documented differences in calving seasons, body size, and ∂ 13 C ∂ 15 N −1 ratios between the eastern and western populations in the Pacific Ocean could be consistent with differential resource use (Aurioles‐Gamboa, Rodríguez‐Pérez, Sánchez‐Velasco, & Lavín, ; Chen et al., ; Endo et al., ; Liu, Chou, & Chen, ). The site fidelity or residency observed for the dolphins in our studied regions (Aurioles‐Gamboa et al., ; Ballance et al., ; Chen et al., ; Soldevilla, Wiggins, & Hildebrand, ) could also reinforce this structure thought dependence on local resources (White & Brown, ).…”