Peak White Shark Season Is Here; Research Raises Many New Questions About The Elusive Predators

The beaches are less crowded with Labor Day behind us, but plenty of activity is happening just beneath the waves. 

It’s peak feeding season for white sharks, and experts say it’s a good time to remind boaters and beachgoers that it’s prudent to take precautions in all salt water, not just off east-facing beaches. While attacks on humans continue to be very rare, researchers say there’s still much they don’t understand about sharks.

 “We’re still learning as we go along,” said John Chisholm, adjunct scientist at New England Aquarium. This summer has proven to be a fruitful one for shark researchers. “We know the population [of white sharks] is rebounding,” he said. It’s clear that a key factor in the recovery of the white shark population is a reduction in fishing pressure from humans. 

 “We’re definitely seeing the benefit of those conservation measures,” Chisholm said. 

 Based on mostly anecdotal data, the number of large white sharks on the Atlantic-facing beaches this summer is lower than in years past, “and that seems to be a trend,” said Gregory Skomal, senior fisheries biologist with the Massachusetts Division of Marine Fisheries. “Many of the sharks we’ve previously tagged seem to be bypassing the Cape and going straight to Canada,” he said. “We’re very curious what’s driving that.”

 Prompted by reports from fishermen and other boaters, researchers last winter decided to shift the locus of this summer’s tagging program.

 “This year we’re seeing a lot of juveniles in Cape Cod Bay,” where food appears to be plentiful and the water temperatures are favorable, Chisholm said. “A lot of people just associate sharks with seals, but some of these smaller sharks we’re seeing, they’re more focused on fish,” he said. “That’s why a lot of the striped bass fishermen are seeing them.”

 In one week last month, Skomal and his team with the Atlantic White Shark Conservatory tagged 17 small white sharks in Cape Cod Bay, primarily fish between five and 5.5-feet in length. It’s another key piece of the puzzle of understanding the habits of white sharks as they age. It’s well established that the area off of New Jersey and Long Island is a nursery for very small sharks, and large ones are known to migrate up and down the coast. 

 “But I’ve always wondered, where’s that intermediate size class?” Skomal said. “Cape Cod Bay is where they were this summer.”

 Are white sharks of this age a threat to swimmers and surfers? It’s not really known, researchers say. These juveniles are focused on feeding on schooling fish like menhaden and mackerel, rather than large prey like seals that might be confused with humans. But it could also be that a young shark is more likely to make a mistake when selecting its prey, “because it’s learning to hunt,” Chisholm said.

 There’s yet another wrinkle in the scientific understanding of white shark behavior. A study recently published in the journal “Environmental Biology of Fishes,” authored by Megan Winton, senior scientist at the Atlantic White Shark Conservancy and co-authored by Skomal and Chisholm, reports the first ever aerial footage of dusky sharks killing and consuming a gray seal in the waters off Nantucket.

 “It surprised me. We thought that the activity of seals being taken out on Great Point was related to white sharks,” Skomal said. With this evidence, researchers now think that dusky sharks are also targeting small seals. While there are accounts of dusky sharks in the area back to the 19th century, the species was heavily fished in the 1980s and remains overfished, and was not the focus of much research — particularly since Cape Cod has been at the northern edge of their range.

 “That could change, of course,” Skomal said. And with evidence of seal predation by dusky sharks, “we wonder, is this what they’ve always done?”

 From the perspective of boaters and beachgoers, the advice about dusky sharks is the same as for great whites.

 “People should be cautious,” Skomal said. “When they get larger, they get bolder and have the ability to take down small seals and sea lions,” he said. 

 Based on tagging data, white shark sightings off Cape Cod peak in September and October, when most beaches are without lifeguard coverage. 

 “When you go into the water, you’ve got to be aware that this is white shark habitat,” Chisholm said. “These sharks aren’t just off Monomoy or Nauset,” he said. Attracted by seals or schools of fish, “they can show up anywhere at any time,” he said. People should avoid swimming alone and should stay out of the water where bait fish or seals are present. Stay near the beach, “and don’t make a commotion in the water that might draw attention,” Chisholm said. 

 People are encouraged to continue reporting shark sightings using the Conservancy’s Sharktivity app, or by emailing Chisholm at masssharks@gmail.com. Data from the public goes a long way in helping researchers understand shark behavior, he said. What’s clear from the research so far is that white sharks are very prevalent in local waters, often in the immediate vicinity of surfers and paddleboarders who “have been investigated” by sharks “and they never know about it,” Chisholm said. Considering the millions of people in the water on the East Coast during the summer, the rarity of shark attacks is telling. 

 “It really is eye-opening that these sharks are not interested in people,” he said. “When you look at the numbers, it just shows how rare it is. But it only takes one,” Chisholm said.