Rising water temperatures could be good news for Alabama’s bull shark population—here’s why

Water temperatures in the Gulf are rising. Just last summer, a buoy in Manatee Bay clocked in a 104° sustained temperature—that’s the maximum temperature you can set on most hot tubs. But it’s looking like some species of animals are thriving under these warmer temperatures, including Alabama’s bull sharks. A recent study found that numbers of bull shark pups in Mobile Bay have increased 5-fold over a 20-year period. I got the chance to talk to the author of that study.

‘Little baby bull sharks’

Mobile Bay and Alabama’s Gulf Coast act as a kind of nursery for bull sharks. Our ecosystem has the right conditions for the babies to grow into big bad bull sharks. And, while we’d normally predict rising water temperatures to spell bad news for ocean-dwellers, study co-author Marcus Drymon says the bull shark population seems to be thriving under these conditions.

“There are some species that will be climate change winners. And some species that will be climate change losers…I think that’s what’s interesting about this study is that it looks like bull sharks are very well adapted to these warming waters, and it looks like their populations will continue to stay healthy, despite the overall detrimental effects of climate change.”

J. Marcus Drymon, Associate Extension Professor, Mississippi State University

So, the baby bull sharks love the warmer water. But does the warmer water mean Mobile Bay is unhealthy? Drymon says no:

“Our findings overall represents an ecosystem that’s healthy. And sharks are important part of that.”

J. Marcus Drymon, Associate Extension Professor, Mississippi State University

Do more sharks mean more shark attacks?

The general consensus that more sharks means more shark attacks is a misconception Drymon says he’s been fighting since the study was published.

“There’s no evidence that links the density of sharks and their populations to an increase in shark attacks.”

J. Marcus Drymon, Associate Extension Professor, Mississippi State University

He believes shark attacks have more to do with the number of people in the water + the population of baitfish that tend to hang out in those waters. And even if the sharks were prone to bite, we don’t have much to worry about in Mobile Bay.

“But to be clear, what we’re talking about and Mobile Bay are these little baby bull sharks. They’re about three feet long. And of course, you know, they have teeth and could bite you and things like that, but no one’s in danger of getting killed by a little baby bull shark.”

J. Marcus Drymon, Associate Extension Professor, Mississippi State University

Why does this all matter?

Evidence of any species thriving under climate change conditions is huge for scientific research. As Drymon said, identifying the “climate change winners” is vital to conservation efforts. That way, we can identify which species may be better suited to surviving in a warmer world + better prioritize who needs saving—and when.

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