USA - Climate change is driving tiger sharks further north. There's a lesson here about how fishing rules work
As climate change warms the oceans, one of its sturdiest predators, the tiger shark, is moving north.
In a first of its kind study that could have implications for how other ocean animals are protected, a team of researchers found tiger sharks had shifted their range north by almost 250 miles. The sharks also began migrating sooner.
“For just every one degree, these sharks are shifting about 14 days earlier into northern areas,” said Neil Hammerschlag, lead author and a shark researcher at the University of Miami Rosenstiel School of Marine and Atmospheric Science. “I was not expecting such striking results. I mean, it's mind blowing and concerning.”
The study was based on 40 years of shark tagging data from the National Oceanic and Atmospheric Administration, as well as satellite tracking and other monitoring.
The shift means the voracious scavengers are spending more time outside restricted fishing zones from Florida to North Carolina, where they are protected from the commercial fishing industry. That leaves them even more vulnerable to fishing practices driving down their numbers.
"What we're finding is that when waters are warming above average, tiger sharks are actually moving poleward outside of these these areas," Hammerschlag said. "Essentially now they're not benefiting from that protection."
As oceans warms, how its inhabitants respond has become a growing concern. Higher temperatures have helped wilt coral reefs. In tropical waters, the UN's International Panel on Climate Change has warned the amount of fish caught could drop by half. The intensity and frequency of dangerous marine heat waves are also expected to worsen.