Social foraging, where animals forage in groups, takes many forms but is less studied in marine predators as measuring social associations in the wild is challenging. We used biologging (activity, cameras and telemetry receivers) sensors to measure social associations and simultaneous behaviour, in white sharks () off Guadalupe Island, Mexico. Animal-borne telemetry receivers revealed that sharks varied in the number of associations they formed and occurred most often when sharks were swimming in straight paths or when they were turning frequently.
View Article and Find Full Text PDFLarge marine predators exhibit high concentrations of mercury (Hg) as neurotoxic methylmercury, and the potential impacts of global change on Hg contamination in these species remain highly debated. Current contaminant model predictions do not account for intraspecific variability in Hg exposure and may fail to reflect the diversity of future Hg levels among conspecific populations or individuals, especially for top predators displaying a wide range of ecological traits. Here, we used Hg isotopic compositions to show that Hg exposure sources varied significantly between and within three populations of white sharks (Carcharodon carcharias) with contrasting ecology: the north-eastern Pacific, eastern Australasian, and south-western Australasian populations.
View Article and Find Full Text PDFFine-scale movement patterns are driven by both biotic (hunting, physiological needs) and abiotic (environmental conditions) factors. The energy balance governs all movement-related strategic decisions.Marine environments can be better understood by considering the vertical component.
View Article and Find Full Text PDFThe twilight zone contains the largest biomass of the world's ocean. Identifying its role in the trophic supply and contaminant exposure of marine megafauna constitutes a critical challenge in the context of global change. The white shark () is a threatened species with some of the highest concentrations of neurotoxin methylmercury (MeHg) among marine top predators.
View Article and Find Full Text PDFShark-cephalopod interactions have been documented in trophic ecology studies around the world. However, there is little information about the encounters between white sharks Carcharodon carcharias and squids in the eastern North Pacific Ocean. Here we provide evidence of interactions between white sharks and large squids in the waters of Guadalupe Island, Mexico.
View Article and Find Full Text PDFThe aim of the present study is to provide an estimate of the number of white sharks Carcharodon carcharias that seasonally interact with ecotourism boats in Guadalupe Island using Schnabel's mark-recapture method and 6316 records of white sharks during 2012-2014. The results of the estimation highlight an abundance of 78 white sharks 95% C.I.
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