1. Sting Operation
Plagues of jellyfish are nothing new, but this summer may well be the worst ever, and we have only ourselves to blame: Overfishing has left fewer predators, and global warming has brought on ideal breeding conditions. The Mediterranean is expected to be the jelly hot spot, but populations will likely spike in oceans worldwide. The sting of Australian jellies can be fatal, but those found off North American coasts usually aren't deadly: "You're just in for a few painful hours. But if you have difficulty breathing or develop hives, get to a doctor ASAP," advises Suzanne M. Shepherd, M.D., of the University of Pennsylvania's PENN Travel Medicine Clinic.
ACTION PLAN: Rinse the area with ocean salt water, then apply vinegar. Flushing it with fresh water--or urine--will only make the sting worse.
2. Big Fish
"You're far more likely to be attacked by the family dog than by a shark," says Marie Levine, executive director of the Shark Research Institute, but attacks on humans off U.S. shores seem to be on the rise. In the entire 20th century 108 Pacific coast attacks were reported; the new millennium has already seen 38, including nine last year, equaling the record high set in 2004.
ACTION PLAN: Avoid high-contrast color swimsuits, stay away from sandbars and mouths of rivers, and check out sharkattackfile.net for more tips. High-risk areas to consider avoiding include Florida's New Smyrna Beach (the so-called shark-bite capital of the world) and California's Tomales Point and Monterey Bay.
3. Storm Surge
Any surfer worth his salt knows that storms bring on the best wave conditions, but hard rains can also sweep debris and sewage into the ocean. The resulting pathogens can linger for up to three days; water safety tests can take that long just to reach the public. And looks are deceiving: The H20 might seem clear and enticing even if it's dangerously polluted.
ACTION PLAN: They may be convenient, but urban beaches are, shall we say, less than pristine. Head to rural stretches of sand whenever possible. If city-center waves are your only choice, then try to "avoid going three days after a hard rain," says Ryan Dwight, Ph.D., director of the Coastal Water Research Project. While you're waiting for the tide to clear, pitch in at a beach cleanup with Surfrider Foundation (surfrider.org).