The young spinner shark was caught off Charlestown. The species normally lives in southern waters.

• A 24-inch spinner shark, a species typically found in waters near Florida, was discovered off the coast of Charlestown, Rhode Island, in September 2024.
• The shark’s partially healed umbilical cord suggests it was very young and raises questions about whether it was born nearby or migrated north.
• Researchers are uncertain if this finding indicates a northward shift in spinner shark nursery habitats due to warming waters or just a rare occurrence.

SOUTH KINGSTOWN – A young shark whose species is normally found in southern waters has raised questions for researchers after its discovery off Charlestown in September of 2024.

The 24-inch spinner shark had a partially healed umbilical cord, indicating that it was less than a year old. Could it have been born nearby? Did the youngster make a long trek north into Rhode Island waters?

Spinner sharks are common in waters off the southeastern United States coast but have rarely been seen near Southern New England, according to Jon Dodd, executive director of the Atlantic Shark Institute in Wakefield.

Joshua Moyer, resident research scientist at the institute and a lecturer at Yale University, said, “According to the literature, most documented nursery habitat for spinners range from the Carolinas to Florida. But here we have a small shark with a partially healed umbilical wound, supporting its designation as a young-of-the-year shark, in Rhode Island.”

Was it a ‘rare stray’ or born nearby?

Still, the researchers say it’s too soon to determine whether the shark was “a rare stray,” or the nursery habitat for spinner sharks is shifting northward because of warming waters caused by climate change. “A single shark does not constitute proof of a nursery,” Dodd said in a press release.

The young shark’s presence in Rhode Island led to the publication of a paper in the Journal of Fish Biology. It was written by Moyer, Dodd and Stephen Kajiura, a professor at Florida Atlantic University and member of the Atlantic Shark Institute’s research advisory board.

“The most fascinating thing about the paper is the size of the spinner shark,” Dodd said. “With a range that focuses on the southern U.S., a mom giving birth here in Rhode Island is unique and opens up a range of questions.”

“Our oceans are changing, known habitats are changing, and what we knew to be the case only 10 years ago may no longer be accurate,” Dodd said. “That is both exciting and disconcerting.”

Most of the world’s oceans have seen a temperature rise, an average rate of 0.14°F per decade from 1901 through 2023, according to the United States Environmental Protection Agency. However, sea surface temperatures have cooled in some areas, including parts of the North Atlantic, according to the EPA.

The spinner shark was caught by Capt. Carl Granquist on Sept. 1, 2024, while he was fishing on the Estrella Domar “just south” of Charlestown, according to Dodd. Granquist wasn’t sure of the species, but he and his mate, Bryce Biggs, measured it and took video of it before returning it to the water, Dodd said. Granquist sent the video to the Atlantic Shark Institute.

“Less than an hour after he (Granquist) released the shark, I received the video, and I was reallysurprised at the size and potential species of the shark,” Dodd said. “I knew it was one of two species of shark and either one would be a pretty unique find here in Rhode Island waters, particularly at only 24 inches in length.”

While spinner sharks closely resemble blacktip sharks, Dodd, Moyer and Kajiura ultimately concluded it was a spinner shark. In 2020, Dodd was also surprised when he spotted a blacktip shark in Rhode Island waters. They also typically live in southern waters.

Spinner sharks live up to their name

The Florida Museum of Natural History describes spinner sharks as “a slender, gray-bronze shark named for its distinctive aerial ‘spinning’ behavior at the surface.”

“When feeding, spinner sharks will often swim through schools of bait fish, spinning along their longitudinal axis, snapping at fish as they move through the water toward the surface,” the museum says. “When they breach the surface, they can be seen spinning in the air – sometimes as much as 20 feet above the water surface.”

Spinner sharks grow to an average of about 6.4 feet and have been blamed for 16 unprovoked attacks on humans, although none have been fatal, according to the museum’s International Shark Attack File. Their “teeth are adapted for seizing small prey rather than tearing at large prey and therefore usually result in relatively minor injuries,” according to the museum.

Though unusual, it’s not the first time spinner sharks have been detected in Southern New England. The Atlantic Shark Institute managed to tag three spinner sharks in the summer of 2022 and is monitoring their movements since the tags send signals when the sharks pass close to acoustic receivers along the East Coast.

Since they were tagged, those spinner sharks have been detected more than 75 times along the East Coast, according to Kimmie Lavoie, a research analyst at the Atlantic Shark Institute.

“Interestingly, we have had no detections further north than North Carolina,” Dodd said. “These sharks love warmer water and more moderate temperatures. A couple have visited Florida, but their home base has been North Carolina.”