Young great white sharks in the Pacific have moved 373 miles northwards off the coast of California, beginning in 2014 with a marine heatwave known as 'the blob' that changed the water temperature over the long term. The sharks' migration was spurred by their original waters becoming too hot, leading them to shift to waters that were previously too cold. This has led to a greater number of sea otters being killed by great white sharks, particularly in Monterey Bay, as well as a decrease in salmon populations.
The great white shark's movement and feeding patterns have the power to greatly disrupt the ocean's food web
South African great white sharks have also begun to move away from the coast towards warmer waters. The populations there have also decreased due to overfishing and pollution that harms the sharks' reproductive systems. Researchers have collected skin samples from the sharks to attempt to find out how these changes are affecting the sharks' biology.
An apex predator, the great white shark's movement and feeding patterns have the power to greatly disrupt the ocean's food web - and their position as a favourite of science communicators to garner public interest in animals means their behavioural changes will not go unnoticed. Professor Malin Pinsky of Rutgers University notes that, 'Without people recording what they saw with apps like iNaturalist, this massive expansion of white shark juveniles might have gone unnoticed.'