NORTH CHATHAM – The sharks hunting seals off Nauset Beach, Chatham and Monomoy every summer are a source of fascination, curiosity and caution. But to researchers, they’re yesterday’s news. This summer, shark experts are focusing their attention on Cape Cod Bay, where white sharks look and behave differently.

 Last summer, a team from the Atlantic White Shark Conservancy and the Massachusetts Division of Marine Fisheries spent around a week in the bay, tagging 17 white sharks. It was confirmation of what local fishermen have said for years: that smaller white sharks hang out there.

 “Those smaller animals are not seal-eaters,” state shark biologist Greg Skomal said. “They’re not really approaching the beaches,” therefore there is less danger to boaters and beachgoers. On the Atlantic side, large sharks are there for one main purpose: to hunt seals close to the shoreline. 

So what are smaller sharks doing in the bay? Some of the answers are coming from the high-tech tracking tags used on sharks found there, including ones that trail video cameras behind the sharks’ dorsal fins, showing what they’re up to.

 “We’re using those camera tags to spy on white sharks in Cape Cod Bay,” said Megan Winton, senior scientist at the Conservancy. The advanced tags provide detailed information on sharks’ movements, much like an activity tracker or smartphone does for people. That change in shark tracking technology has transformed research in the past decade, Skomal said.

 “You can see how our scale has changed,” he said. Initially, acoustic tags were the only tool available and could provide limited location information about tagged sharks that had to be downloaded and evaluated every few months. “And now we know what they’re doing every second,” Skomal said. 

 The work in Cape Cod Bay represents a frontier for local shark researchers where there is still much to learn. It seems like the bay is an important habitat for growing white sharks, “so we want to better understand that,” Skomal said.

 A study was done a few years ago that evaluated how deeply sharks swim, and some of the hundreds of sharks tagged by researchers ventured into the bay from their hunting grounds off the outer beach.

 “What we did find is that in the bay, they did use a lot deeper depths because there’s more depth available, but also they don’t seem to be as concentrated the way they are along the Outer Cape,” Winton said. The smaller white sharks seem to be curious about the seals they encounter near haul-outs at Manomet and Jeremy Point, but they’re not hunting them.

 “It’s a different demographic,” Skomal said. “We’re curious about what that segment of the population is doing and how it’s utilizing the bay, and whether the bay is actually providing important essential habitat for the species.”

 While white shark research off Cape Cod happens during the summer and fall, the same sharks are being tracked by researchers in other places.

 “Cape Cod is one of the few white shark hotspots, and it was the first white shark hotspot in the Northwest Atlantic,” Winton said. “But it is a very tiny portion of this population’s overall range.” Acoustic buoy data shows tagged sharks moving to the Gulf of Mexico, the Bahamas and off the Southeast U.S. coast during the winter, where they are also less concentrated — and therefore can’t be tagged with harpoons the way they are here. There, tagging has happened with the support of charter fisherman Chip Michalove, who angles for white sharks so researchers can tag them. “We’ve been able to learn a lot from each other, so it’s been a really productive partnership,” Winton said.

 There also seems to be a resurgence of white sharks off the Canadian Maritimes; like their “arrival” off Cape Cod more than a decade ago, “they do just seem to be coming home to these areas that we know were historically important to the species,” Winton said. Their return to Canada, as to Cape Cod, appears linked to the increase in seal populations. Once subject to bounties designed to protect fish stocks, seals are now protected and have made a dramatic comeback. 

 “Remember, we knocked seals down pretty hard here in the U.S., but the same thing also occurred in Atlantic Canada,” Skomal said.

There was also fishing pressure on sharks directly. “Based on the best available data out there, we think the population in the Northwest Atlantic declined by almost 80 percent as fishing pressure ramped up in the ‘70s and ‘80s,” Winton said. As shark populations begin to rebound, so has the interest in fishing for them. Except for a zone between Plymouth and Provincetown, including Cape Cod Bay, and stretching south from Provincetown toward Monomoy, it is legal to fish for white sharks in Massachusetts, Skomal said. But not all follow the rules.

 “We have had people who have come into those areas and...have successfully tried to catch large white sharks,” he said. “That’s not good for public safety, it’s not good for the species.”

Warmer weather will soon be drawing more people to the water, and shark experts have a message: don’t be complacent about shark safety.

The regional white shark working group has already met this spring, and public safety representatives from around the Lower Cape expressed concern that, with people growing used to the idea of sharing local waters with sharks, they might begin to disregard safety advice.

 Off the outer beaches, white sharks are present in the summer and fall to hunt seals, not to menace humans. They spend about half of their time in water less than 15 feet deep, “which is the area where they’re most likely to overlap with recreational water users,” said Meg Winton of the Atlantic White Shark Conservancy. Seals know that sharks are present, “so the seals stay as close to the shore as they can to stay out of the reach of sharks, but there are a lot of beautiful public swimming beaches along the Cape,” she said.

 The Conservancy has an extensive public outreach program, meeting people at beaches, boat shows and other events, and at its shark center in North Chatham, to talk about shark research and safety. It has published a “Shark Smart” poster, soon to be translated into Spanish, French and Portuguese, offering safety tips.

 “Don’t swim with shark food. Don’t swim with seals, don’t swim in the middle of big schools of fish,” she said. “And watching your depth is really important; it’s more important than distance from the beach.” Avoid swimming at dusk or dawn or in murky water, avoid splashing, and follow the instructions of lifeguards. 

 The Conservancy’s popular Shartivity app also provides the location of recent shark sightings and allows the public to report their own sightings. But experts say there are no perfect warning systems or shark deterrents, and there may never be.

 “That’s where the outreach component is so important,” Winton said. Residents and visitors need to be informed about the presence of sharks and their activities so they can modify their own behavior when around the water. “That is a really important part of the story here,” she said.

 Learn more at www.AtlanticWhiteShark.org.