Fastest Swimmer: Sailfish

Dave Kerstetter tags sailfish for Nova Southeastern University Oceanographic Center

2 min read
Photo of a sailfish
Photo: Reinhard Dirscherl/Getty Images

This segment is part of the IEEE Spectrum series “Fastest on Earth.”

Fastest Swimmer: Sailfish


Susan Hassler: While we’re in the water, consider the ocean’s fastest creature. Observers are astounded by its powerful muscles, athletic out-of-water leaps, and otherworldly beauty. Ari Daniel Shapiro reports.

Ari Daniel Shapiro:Dave Kerstetter remembers the first time he saw one.

Dave Kerstetter: It was in Bermuda, and the water was almost a purple, it was so deep blue.

Ari Daniel Shapiro: He was on a boat catching, tagging, and releasing blue marlin for research. But on this particular day in 2000, his team hooked a giant sailfish instead.

Dave Kerstetter: It was an electric blue; it was throwing its sail up. I was just awestruck by how pretty it was.

Ari Daniel Shapiro:Sailfish are named for their dorsal fins that resemble giant sails. And if they get caught and pulled to the surface, they put on quite a show.

Dave Kerstetter: A fish will make short little jumps out of the water, and do these running leaps across the surface of the water. Sometimes they’ll leap up 4 or 5 feet out of the water, shake their heads and their bills violently, and then duck back in the water and continue the fight.

Ari Daniel Shapiro: An angler once timed a hooked sailfish pulling out his fishing line. The speed? Sixty-eight miles an hour—considered the fastest of any underwater creature.

Dave Kerstetter: That big large sail dorsal fin folds down, actually, within a groove alongside their back. And so they become almost bullet-like.

Ari Daniel Shapiro: Kerstetter studies sailfish at Nova Southeastern University Oceanographic Center in Florida. He catches and tags them, to track their swimming and diving behavior, and to monitor their survival after being caught and released by anglers required to throw them back into the water. As for that sailfish he hooked in 2000…

Dave Kerstetter: It’s awfully anthropocentric to imagine a sailfish looking at you with disdain like that, but that’s definitely the sense I got.

Ari Daniel Shapiro: He released the fish, and it vanished as quickly as it appeared, racing back into the dark-blue depths. I’m Ari Daniel Shapiro.

Photo: Reinhard Dirscherl/Getty Images
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