Great white sharks have been reported off Point Judith in the past, and researchers finally got confirmation recently when an acoustic receiver signaled a shark not far from shore, according to Jon Dodd, executive director of the Atlantic Shark Institute in Wakefield.
The shark, a female about 9 feet long, was detected in late August by an acoustic receiver in 30 feet of water less than a mile from shore, according to Dodd.
“We’ve had reports of white sharks being spotted in that area over the last few years but this is the first confirmed detection using this technology,” Dodd said.
As part of a five-year study, Dodd and Conor McManus of the Rhode Island Department of Environmental Management have set nine acoustic receivers in the waters off Rhode Island to detect the presence of great whites.
The study, which is in its second year, detected seven different sharks this season. Last year, it detected four sharks but also had fewer receivers in the water. Dodd reported the findings Wednesday after pulling the receivers from the water and retrieving the information.
The other recent white shark detection was picked up by a receiver off Block Island in September. That receiver is about 10 miles southeast of Block Island. It detected an 8-and-a-half-foot long female.
Dodd knows details such as the sharks’ gender and size, because researcher Greg Skomal, of the Massachusetts Department of Marine Fisheries, put electronic tags on them last year off Cape Cod, according to Dodd.
Since neither shark was detected here at any other time this season, Dodd believes both sharks were just passing through Rhode Island waters. They might have spent the summer off Cape Cod, which is popular with great whites because of its high seal population, and swum past Rhode Island on the way to warmer southern waters, he said.
Skomal has also set up acoustic receivers off Cape Cod. When Skomal retrieves his data, Dodd will check to see if the same sharks were detected off Cape Cod this summer.
Dodd said, “We are beginning to see patterns emerge from this data and that’s an exciting first step in this research.”
The Rhode Island receivers have been pulled from the water for the season, but Dodd will soon head to South Carolina to research great white sharks there. He also spent time this season researching sharks off Maine. White sharks are capable of regulating their body temperatures and can roam a long way, Dodd said.
Is it likely that more great whites are swimming in Rhode Island waters? Probably. Dodd notes that only sharks with working electronic tags are picked up by the acoustic receivers. He says only a small percentage of white sharks have been tagged.
Next year, the researchers plan to deploy more acoustic receivers off Rhode Island. Dodd says they’re also expanding their “collaboration with other New England states to build a broad based picture of white shark movements throughout the region.”