TAMPA, Fla. (WFLA) — Swimming side by side with sharks is just a fact of life in Florida. But increasingly it’s becoming common in places not accustomed to these shark encounters. That’s because along the U.S. East Coast and the U.S. West Coast as well, warming waters are now shifting shark migrations.
As Dr. Chris Lowe, Director of the Shark Lab at Cal State Long Beach explains, “We are just starting to see what we think are the implications of climate change on this range shift of these sharks.”
Between 2014 and 2019 – during the infamous warm blob event – a curious thing started to happen along the California coast. Warm water pushed juvenile White sharks hundreds of miles north.
“Typically the white shark nursery habitat is off Southern California but a few years ago we started to see white sharks aggregating up in Monterey Bay and that area is historically too cold for them,” said Lowe. It’s oceanographically warming up faster than we thought possible, so this is the concern about global climate change, that the waters are warming faster than we predicted.
Rare marine heatwaves, like the blob, are now 20 times more common because of human-caused climate change. But for now, this warming water appears to be working out for California’s White sharks.
Lowe explains, “White sharks may actually be beneficiaries of climate change. As long as there is plenty of food, which there appears to be, that population is gonna do well, but that may not be the case 20 years from now.
And that’s what worries Dr. Neil Hammerschlag of the University of Miami. He’s found a similar effect off the East Coast.
“Ocean warming is actually causing the Tiger sharks to alter their migrations, they are extending their migrations further north, they are spending more time there, and they are arriving earlier in the year.
Hammerschlag says tiger sharks have even moved into the historically cold waters of the northeast – a place they haven’t been before.
And while this can inadvertently cause more run-ins between people and sharks, Hammerschlag doesn’t feel this is cause for concern.
“In general we don’t have to fear shark bites because thankfully sharks really don’t like to be around people, generally when sharks see people they go out of their way to avoid people. Fortunately for us, humans are just not on the menu,” reassures Hammerschlag.
But while this may not be dangerous for humans, it can be deadly for sharks.
“Because ocean warming is altering their movements, the timing and where they are going, there’s actually now a greater mismatch between where the Tiger sharks are and these protected areas and as a result, they are now more exposed to being captured in these fisheries,” warns Hammerschlag.
In an interesting twist, Dr. Hammerschlag has reverse engineered the process. Instead of just studying how climate change impacts sharks, his team has recruited 18 sharks to study climate change by outfitting them with instruments to measure temperature at the surface and at depth. The data is then beamed back by satellite. In the future they hope to expand this program to help improve weather forecast models.