Andrew Ford, and Alex N. Gecan

Asbury Park Press

OCEANPORT – The excruciating full-body muscle pains let Matt Carlo know he wasn't stung by a normal jellyfish.

Experts determined the 20-year-old Lincroft man was most likely wounded by a "clinging jellyfish," a dime-sized invasive species armed with potent venom lurking in the back bay waters along the Jersey Shore. While authorities say it's rare to bump into one, those who do could suffer severe pain.

Carlo found that out first-hand about 11 p.m. Saturday. He was wading with friends in the Shrewsbury River near a waterfront home. He felt a jellyfish sting on his side, under his left arm. He's been stung before, and he saw the typical red lines of the wound. But the pain was like nothing he ever felt – so much so that he was hospitalized for nearly three days, needing morphine to dull the pain.

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“I thought I was going to die," he said. "That's how much pain I was in.”

Clinging jellyfish are native to the Pacific, but now they've found their way to the Jersey Shore. Paul Bologna, director of the Marine Biology and Coastal Sciences Program at Montclair State University, said the first jellyfish was found two weeks ago by a fisherman in the shallow waters of Barnegat Bay in Bay Head. DNA analysis confirmed that specimen was a clinging jellyfish, according to Bologna. Since then, three more have been found in the Shrewsbury River.

The tiny, semi-transparent critters prefer shallow areas, clinging to seagrass by day, swimming around at night or when agitated.

"This is the first documented case of these little guys we've got in New Jersey," Bologna said.

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To try and track down how many clinging jellyfish have invaded New Jersey's waterways – and in response to Carlo's injury – researchers from the Department of Environmental Protection trawled the waters of the Shrewsbury River and northern Barnegat Bay Thursday, according to research scientist Joseph Bilinski. Though they found no clinging jellyfish on those outings, they're working to determine where the jellyfish are living and how many are there. It's hard to know how they got there, or how long they've been there.

Clinging jellyfish made their way to the East Coast more than 100 years ago. They were first reported in Woods Hole, Massachusetts, in 1894, according to Bilinski. The jellyfish are not densely populated and bumping into one is unlikely. He compared their sting to that of a bee, reactions vary – some people could go into shock, for some it's just painful.

But the good news for beachgoers is that while the clinging jellyfish can be found in calm bays and rivers, they likely won't be found in the turbulent waters off ocean beaches because these jellyfish don't fair well in waves.

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There aren't any beach closures, but Bologna – who was part of the DEP's research mission looking for the jellyfish – urged the public to be cautious, especially in when venturing into the water at night, when the jellyfish are more active.

"Make sure you have a flashlight and look before you leap," he said.

That's advice that Carlo likely wished he had taken.

When he was first stung, he didn't know that he had just been stung by a rare jellyfish. But then the red lines of the wound swelled up together to form a red mark about the size of his hand. Within an hour, the pain spread. It dwarfed the pain of the appendicitis he had a few months ago. He compared it to a charley horse-like cramp across his whole body.

“The pain wasn’t on my skin, the pain was inside," he said.

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When the pain didn't get any better, his mom took him to Riverview Medical Center about 2 a.m. Sunday. He said the staff treated it like a normal jellyfish sting. He got a shot of ibuprofen, they told him to go home, take a hot shower and he would be fine in a few hours.

He wasn't. He took the shower, but the pain was so bad he couldn't lay down.

“My mom was crying I was in so much pain," he said. "They didn’t know what to do.”

He went back to the hospital about 5 a.m.

This time they gave him a morphine injection.

“And that really only took the edge off.”

He stayed in the hospital on morphine for about 24 hours.

Carlo is a graduate of the Marine Academy of Science and Technology, based at Sandy Hook. While in the hospital, he texted his old oceanography teacher. He said she put him in touch with Bologna.

Wednesday, Bologna went to the spot where Carlo was stung. Bologna's students spotted two jellyfish bobbing off a bulkhead.

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Based on their presence and Carlo's reaction, Bologna determined he was most likely hurt by a clinging jellyfish.

Bologna also met Wednesday with two little girls in Monmouth Beach who gave him a jellyfish and said they saw more.

"I just wasn't expecting to find this many this fast," Bologna said.

And he warned that they might have found a home here: "If they've become established. They're going to remain here.".

Carlo stressed that the medical community should be aware of the danger posed by the clinging jellyfish, expressing worry that a small child or elderly person could be seriously affected.

The pain of his sting didn't wear off until he woke up Monday morning. The site of the sting was still tender Thursday. And while he still loves fishing, boating and swimming, he's going to stick to the ocean.

“I definitely won’t be swimming in the rivers anymore," he said.

Andrew Ford: 732-643-4281; aford3@gannettnj.com