Mountain Sharks

If you want to avoid sharks, then steer clear of the mountains. No, we’re not talking about the next “Sharknado” movie. It’s underwater mountains—called “seamounts”—that you want to avoid. A recent study found there were 40 times more sharks around a couple of shallow seamounts than in the surrounding open ocean.

Researchers spent about 20 months perusing three seamounts near Ascension Island—a lonely spot in the South Atlantic Ocean. The peaks of two of the seamounts rose to within a few hundred feet of the surface, while the third was deeper.

Scientists studied life in the region with underwater video cameras, surface counts, and sonar scans. And they placed tracking devices on several sharks and tunas.

They found that all forms of life were more abundant around the two shallower seamounts, from the tiniest organisms all the way up to top-level predators. But the higher up the food web, the greater the abundance compared to the open ocean.

Some of the tagged sharks and tunas hung around a single seamount. A few others made appearances at both. And one intrepid shark journeyed up to 85 miles out to sea.

The researchers aren’t sure why there’s such a concentration of sharks and other life at the seamounts. Currents may push more prey up the sides of the mountains, attracting larger fish. Or perhaps the currents just make it harder for prey to escape. Whatever the reason, the sharks just loved hanging around these underwater mountains.