Rare Spinner Shark Discovered in Rhode Island Waters - Finding Published in Journal of Fish Biology
GoLocalProv News Team
Rare Spinner Shark Discovered in Rhode Island Waters - Finding Published in Journal of Fish Biology
According to ASI, on September 1, 2024 Captain Carl Granquist was fishing just South of Charlestown, Rhode Island when catch landed on the deck of his boat, the F/V Estrella Domar.
ASI says that upon finding a small shark thrashing on deck, Granquist videoed the shark, not sure of the species, and along with his mate, Bryce Biggs, measured the 24-inch shark before releasing it.
GET THE LATEST BREAKING NEWS HERE -- SIGN UP FOR GOLOCAL FREE DAILY EBLASTWhen Granquist shared the video with the Rhode Island-based ASI to see whether they could make a positive identification, his observation "kick-started a dive into the scientific literature that culminated in a new research paper published in the Journal of Fish Biology."
Shark Institute Jumps In
“Less than an hour after [Granquist] released the shark, I received the video and I was really surprised at the size and potential species of the shark," said Jon Dodd, ASI Executive Director. “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."
Dodd noted that ASI has partnered with Granquist "for many years" and that he has been an "excellent contributor to a number of our shark research projects."
According to Dodd, he knew that he was looking at either a spinner shark or blacktip shark. Both species are well-documented along the southern east coast of the United States and can be difficult to tell apart, said Dodd.
To assist, Dodd turned to Dr. Joshua Moyer of Yale University and Dr. Stephen Kajiura of Florida Atlantic University, who is also a member of the ASI’s Research Advisory Board.
Dodd said that Kajiura "concurred that identification was difficult but noted that such a young shark of either species Rhode Island waters had rarely been documented and was worth investigating."
Moyer, who is the lead author of a paper documenting this find, "reviewed the scientific literature reliable diagnostic criteria to identify the species in Granquist’s video."
"That was quite a scavenger hunt,” said Moyer. “These are very similar species, and many historic works on sharks in New England either admit that their identification of these sharks could be mistaken or they do not tell you how they made their identification.”
According to ASI, measurements along the snout were key for species distinction, and using frame-by-frame analysis, Moyer confirmed Dodd and Kajiura’s hunch that the shark in question was a spinner shark.
Spinner Sharks in Focus
The waters of southern New England are not currently recognized as nursery habitat for juvenile spinner sharks, says ASI.
“According to the literature, most documented nursery habitat for spinners range from the Carolinas to Florida,” said Moyer. “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.”
Whether the nursery habitat is shifting northward because of climate change or the shark in question is a rare stray is too soon to tell, said ASI, noting that a "single shark does not constitute proof of a nursery."
“This discovery raises a number of really important questions and it’s the very reason we do this critical research," said Dodd. "The spinner shark captured by Captain Granquist and crew support the inclusion of southern New England in the species’ range."
“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," he added. "That is both exciting and disconcerting.”
The paper was recently published in the Journal of Fish Biology by authors Moyer, Dodd, and Kajiura. You can learn more about the Atlantic Shark Institute at www.atlanticsharkinstitute.org.