This summer, eight great whites already have been spotted off various Cape Cod beaches, though some of the sightings may involve the same shark. The National Park Service just issued precautionary guidelines for Cape Cod swimmers.
Skomal has been tracking great whites off Cape Cod for years: He and his colleagues tagged five in 2009 and 17 in 2012. The probable reason for the increase is a resurgence in the seal population, which has been recovering over the past four decades since enactment of the Marine Mammal Protection Act, which outlawed a kind of hunting that caused the seals' precipitous decline. The National Oceanic and Atmospheric Administration estimates that the seal population in the western North Atlantic has increased by tens of thousands over the past few decades.
"I fully anticipate that the white sharks will continue to take advantage of this resource," Skomal said, noting that half of the sharks tagged in 2011 came back to the areas where they were tagged the following year. (Researchers use a few different tags, including acoustic ones that rely on radio transmitters and satellite tags) "Everything is clicking for [the sharks] and the cafe is open for them. They will continue to take advantage of that."
A spate of shark strikes in 2001 that claimed the lives of swimmers — including two in the Mid-Atlantic, 10-year old David Peltier off Virginia Beach and 28-year-old Sergei Zaloukaev off Cape Hatteras, N.C. — earned the season the nickname "Summer of the Shark." Zaloukaev was the last person to die from a shark bite in the Mid-Atlantic. (His girlfriend was bitten also but survived.)
Still, there have been nonlethal events. Last month, 63-year-old surf instructor Barbara Corey was bitten off Holden Beach in Brunswick County, N.C., the first Mid-Atlantic shark strike this year. Last year there were two, both in North Carolina, where 6-year-old Brooklyn Daniel was struck off Brunswick and 33-year-old Megan Konkler was bitten off Nags Head Beach.