Tiger shark migrations altered by climate change, new study finds

The effects of ocean warming on tiger shark movements in the Western North Atlantic were evaluated by Neil Hammerschlag and colleagues in a new study. Over the past 40 years, shark distributions have expanded parallel to rising temperatures. Satellite tracking of sharks over the past decade has shown that their annual migrations have extended farther poleward and arrival times to northern areas have also been earlier in the year during warm periods, which has resulted in decreased protections from fishing. Changes in encounter rates with humans, shark vulnerability to fishing, and disruption of predator-prey interactions are possible consequences of climate-driven alterations. Credit: Bianca Rangel.

The locations and timing of tiger shark movement in the western North Atlantic Ocean have changed due to rising ocean temperatures, according to a new study led by scientists at the University of Miami. tiger shark movements outside of protected areas have been shifted by the climate driven changes.

The tiger shark's movements are constrained by the need to stay in warm waters. The waters off the U.S. northeast coastline have historically been too cold for tiger sharks, but recent warming has made them suitable for the shark.

Neil Hammerschlag is the director of the UM Shark Research and Conversation Program and the lead author of the study. Changes in tiger shark movements outside of marine protected areas may leave them more vulnerable to commercial fishing.

Hammerschlag and the research team discovered these climate-driven changes by analyzing nine years of tracking data from satellite tagged tiger sharks, together with nearly forty years of conventional tag and recapture information supplied by the National Oceanic and Atmospheric Administration.

The study found that tiger shark migrations extended farther poleward when ocean temperatures were warmer than average.

The results may have a bigger impact. Hammerschlag said that the changes to tiger shark movements may alter predator-prey interactions, leading to ecological imbalances and more frequent encounters with humans.

The tiger shark is an apex predator and the warming of the ocean alters its distributional range, migratory timing and spatial protections.

The study's authors are Neil Hammerschlag, Laura McDonnell, Mitchell Rider, Ben Kirtman, and others.

The tiger shark is an apex predator that has its distributional range, migratory timing, and spatial protections altered by ocean warming. The DOI is 10.1111/gcb.16045

The Global Change Biology journal has information.

A new study found that tiger shark migrations were altered by climate change.

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