"These guys have a really bad sting," said Dr. Paul Bologna, a marine biologist at Montclair State University.
VENTNOR CITY, New Jersey (WPVI) -- Here's a warning for those who prefer swimming in the back bays of the Jersey shore instead of the ocean.
Marine experts say a dangerous sea creature could be hiding beneath the surface of the water -- a clinging jellyfish.
"They should be pretty concerned if they're out in the back bays, especially shallow water where there is a lot of vegetation, whether it's algae or seagrass because these guys have a really bad sting," said Dr. Paul Bologna, a marine biologist at Montclair State University.
For some who like to vacation at the Jersey shore, what's lurking in the water could be a concern.
"I don't really feel like getting bit going in the water," said Robert O'Brien of Manalapan, New Jersey.
"It's concerning, especially for the kids of course," said Tarrah Triglia of West Chester, Pennsylvania.
Clinging jellyfish have been spotted in a number of locations.
"Most recently they were found all the way down in sort of the Stone Harbor, Cape May area down in the second Thorofare Bridge," said Bologna.
Bologna said if you get stung, you won't feel their powerful effects till hours later.
"Often times four or five hours afterward somebody heads to the hospital because they're in incredible pain. They've got these paralysis toxins that sort of course through somebody's body," he said.
Daniel Schall, a lieutenant with Ventor Beach Patrol, says now these clinging jellies are on his radar and he's getting the ball rolling on what he needs.
"We happen to be very lucky that the emergency room in Atlantic City is two minutes away so we can transport fairly quickly," said Schall.
According to the New Jersey Department of Environmental Protection, if you get stung, "Rinse the area with salt water and remove any remaining tentacle materials using gloves, a plastic card or a thick towel. If symptoms persist, pain increases instead of subsiding, seek prompt medical attention."
If you encounter a clinging jellyfish, do not touch it. Avoid contact and do not collect it.
If you see one, email the Montclair State University research team with a specific location (GPS coordinates, if possible) and an image to bolognap@montclair.edu and or joseph.bilinski@dep.nj.gov.