The official start of summer is still a month away, but white sharks are back on Cape Cod.
Shark biologist John Chisholm reported seeing two white sharks — the first reported this season — off Monomoy on Wednesday.
And on Thursday, two shark scientists met with reporters at the Atlantic White Shark Conservancy in Chatham to talk about what to expect this season.
As in past years, real-time acoustic receivers will detect tagged sharks off five beaches along the Outer and Lower Cape: Head of the Meadow, Lecount Hollow, Newcomb Hollow, Nauset Beach, and North Beach.
But be aware that most sharks are not tagged, said Conservancy scientist Megan Winton.
“We like to remind the public that this … technology is not intended to be an early warning system,” she said. “It's a proxy for the activity of the population as a whole.”
Real-time detection helps educate the public about how much time sharks are spending in the area, said scientist Greg Skomal, longtime head of the shark research program at the Massachusetts Division of Marine Fisheries.
“We don't think of it as a public safety tool as much as an educational tool,” he said. “Because … lifeguards [and] public safety officials get a sense of how frequently a tagged shark is around, how long it stays there, that kind of information.”
More than 70 other receivers record data that gets collected at the end of the season.
Researchers are also using camera tags, which detach from the shark after about a day, and drone video to learn more about white sharks off Cape Cod.
Separate from the tagging efforts, scientists have recorded details of 57 seal predations off the Outer and Lower Cape over the last nine years.
Some happened in just 5 feet of water, but sharks are feeding under a variety of conditions, Winton said.
“When they're here, they're actively patrolling the beaches,” she said. “And they take their opportunity when they have it, essentially.”
More sharks have been seen feeding in the afternoon than in the morning, but that’s at least partly because more people are on the beaches to see them, the researchers said.
Skomal said they hope to gather more unbiased data on predations from camera tags and maybe drones, too.
