Video still of one of the great white sharks we saw

Article: Wired on white shark buoyancy and diet featured an article describing research done on tagged white sharks off California in the United States. The research supervisor, Barbara Block, was involved with the creation of the Shark Net app, about which I’ve gotten excited previously. The sharks were tagged as part of the Tagging of Pacific Predators Program (TOPP), using satellite pop-up tags. These tags release after a certain amount of time, and upload some information immediately via satellite. Once retrieved, further data can be accessed on the tag. (These tags are different to those used by the Ocearch team who participated in the Shark Men documentary series.)

Pacific white sharks visit the Farallon Islands to feast on elephant seals, and then migrate out into the Pacific Ocean to the shared offshore foraging area (SOFA). During this time they lose fat, and researcher Gen Del Raye hypothesised that this would affect their buoyancy, and hence the ease with which they dive. Del Raye calibrated his model by studying a captive white shark at the Monterey Bay Aquarium.

Del Raye’s results suggest that the sharks don’t eat at all during their migration, since their buoyancy seems to decline steadily while they’re out at sea. Implications of the research include the fact that not only is it important to conserve white sharks, but their seal prey too – since those meals before setting out to sea seem to be incredibly important for building fat reserves in the sharks’ livers.

Read the full article here.

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Lapsed mathematician, creator of order, formulator of hypotheses. Lover of the ocean, being outdoors, the bush, reading, photography, travelling (especially in Africa) and road trips.

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