Climate change is expelling sharks from their habitats: Researchers have discovered that sharks are leaving their coral reef homes as ocean temperatures rise due on the back of the worsening climate crisis, The Guardian reported earlier this week, citing a Communications Biology Journal study (pdf). The migration negatively affects the already endangered reef sharks which play a crucial role in maintaining the balance of coral reef ecosystems.

What they found: The study tracked over 120 gray reef sharks in the Chagos archipelago in the central Indian Ocean between 2013 and 2020. During increased ocean stress, especially during the 2015-2016 El Niño phenomenon, the sharks spent less time on the reefs and took up to 16 months to return to their normal habitat. However, some sharks stayed longer on healthier reefs, suggesting that protecting these areas from human damage could help retain shark populations.

It’s getting hot in here: Sharks are cold-blooded with their body temperature linked to water temperature. “If it gets too hot, they’re going to need to move,” research lead David Jacoby told the Guardian. “We think many are choosing to move into offshore, deeper and cooler waters, which is concerning. Some of the sharks were disappearing entirely from the reef for long periods of time.”

The consequences could be massive: Tropical coral reefs host a quarter of all marine fish and support the livelihoods of at least 500 mn people. However, they are being severely damaged by ocean warming, overfishing, and pollution. Most coral reefs could be lost if global temperatures rise by 2 degrees celsius with direct damage from severe bleaching events annually by mid-century even if pledges from the Paris Agreement are met.

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