Great white sharks returning to northeast Atlantic
After reaching nearextinction levels, populations nearly restored
GREENWICH — The New England coastline is experiencing a great white shark renaissance.
After reaching nearextinction levels from aggressive fishing, the white shark population off Long Island and Cape Cod has been nearly restored over the last two decades due to careful conservation of both sharks and their juiciest prey, the gray seal, experts say.
For the last 50 years, the white shark has eluded scientists. But, as young sharks approach shallow waters in Cape Cod and tracking technology improves, area researchers are collecting new data on where baby white sharks grow up, where they swim and when they feed, as well as their potential vulnerability to human activity.
“We’ve learned a lot in a very short period of time,” said Tobey Curtis, a fisheries manager for the National Oceanic and Atmospheric Administration, during a talk at the Bruce Museum Tuesday night.
Curtis is at the forefront of research on young white sharks that swim in northeastern waters. He said the growing white shark population is due to the nursery off the South Shore of Long Island, where young pups can feed and grow up without tangling with adult white sharks.
Scientists have known about the possibility of a nursery since the 1980s, but could not be certain without tracking the movements of the resident sharks.
They do not know where the sharks are born, but the pups spend their first summer “in the Hamptons,” and — as any discerning shark would, Curtis joked — spend winter in the Outer Banks of North Carolina. His group published its findings in 2018.
When they go on expeditions, team members catch sharks with a hook and line, and the shark is brought out of water using a boat lift. Scientists afix the tag, take swabs and samples, and then release the animal. Curtis and his team have partnered with OCEARCH, an organization that raises money to track marine life and educate people about sharks, dolphins and turtles, to tag about 20 sharks.
By tracking sharks’ movements, Curtis said his team has found the sharks are vulnerable to human activity in the Long Island area. One big problem he deals with as a fisheries manager for NOAA is bycatch: The high volume of commercial fishing of squid, cod and flounder means sharks can be caught in nets and harmed.
The effect of other activity is not yet clear. Data show the sharks’ movements will overlap with construction of wind farms in northeastern waters. But scientists do not yet know what the effect on the population could be, Curtis said. The construction noise could scare away potential food sources, or the windmills, once installed, could create artificial reefs that attract fish species and sharks.
Curtis and his team share data with dozens of research scientists at major universities, studying feeding habits, teeth, eyes and internal parasites, among other topics.
One of the sharks tagged in the study, Cabot, made headlines — and surprised scientists and Greenwich residents recently — when he seemed to surface in Long Island Sound. OCEARCH sent out notices on social media that Cabot’s tag pinged off the coast of Old Greenwich.
Curtis, however, said he doesn’t think the shark paid Greenwich a visit.
The tagging devices can be off by 15 to 20 miles, Curtis said. Cabot registered near Greenwich, but then also off the southern Long Island shore later the same day. It is unlikely the white shark entered the Sound — which does not have an environment conducive to sharks — and swam back out in a day.
Further, none of the sharks Curtis has observed have ventured into the Sound.
“There is no way it could have swung around and back out in a day, unless it was sneaking through the East River, which is unlikely,” Curtis said, joking.
John Kanaly, the communications manager of OCEARCH, said Wednesday it is hard, given the data, to be 100 percent certain if Cabot was in the Sound, since the organization received detections from both sides of Long Island.
Kate Dzikiewicz, the science fellow at the Bruce Museum, applauded Curtis’ efforts to tag sharks. It is difficult to preserve an endangered population if conservationists do not know how many white sharks there are, she said.