For beachgoers, plain old accidental drowning is still the big danger, with some 3500 fatalities annually in the US, according to the Centres for Disease Control and Prevention, not counting drownings related to boating.
Still, George Burgess, director of the International Shark Attack File at the University of Florida, told Reuters this year could be a record high for unprovoked shark attacks. If so, it would follow a trend that began last year when 98 people around the world were bitten by sharks, setting the world record for attacks. The previous record, set in 2000, was 88 attacks.
"These are entirely predictable things just as you can predict drownings or car accidents as a result of this being a huge holiday weekend," Burgess said of the weekend's incidents.
The reason is simple maths: The world contains ever more people, recreational beaches are more crowded and there are ever more sharks.
According to a 2013 release by the NOAA, the US coastal population is predicted to grow from 123 million people to 134 million people by 2020. And that's to say nothing of the holiday-makers who visit both coasts' beaches.
Meanwhile, a 2015 study by the NOAA Fisheries Service found that shark populations have been increasing on the East Coast, an ongoing trend.
"We've seen an increase in the number of sharks in every survey since 2001; that reflects management efforts to conserve the populations of various shark species," Lisa Natanson, the scientist at the Narragansett Laboratory of NOAA Fisheries' Northeast Fisheries Science Centre who led the survey, said in a press release. The survey samples coastal waters from Florida to Maryland and Delaware, where migratory sharks concentrate as the waters warm in the northern spring and summer.
The last survey, in 2012, found 1831 sharks. The 2015 survey found 2835, which is a 55 per cent increase.
Gregory Skomal, a shark expert with Massachusetts's Department of Fish and Game Division of Marine Fisheries, told Newsweek that shark populations decreased from the late 70s to the early 90s as their meat became more popular. Since sharks grow so slowly and only reproduce a few times in their lives, they are particularly prone to overfishing. But with better wildlife and fisheries management across the country since the 90s, those populations have been slowly recovering.
One last factor that could contribute to shark attacks is how many people are actually spending time in the water. Burgess said as the ocean's temperatures continue to rise, it will become increasingly attractive for swimmers looking to cool off.
Others said this is already happening.
"More people are using the ocean now for recreation than ever before, so there is no doubt that we're putting more people in the water," Chris Lowe, professor in the Department of Biological Studies and the CSULB Shark Lab at California State University Long Beach told Men's Journal in 2014. "You put more people in the water and add more sharks to coastal areas, you will have more shark-human related interactions."
The good news for the US is that, while the country leads the world in unprovoked shark attacks, its victims are more likely to live. In 2014, the fatality rate for shark attacks in the US was 1.7 per cent compared to 12.8 per cent worldwide, the Atlanta Constitution-Journal reported.
