They call it the invasion of the jellyfish, and it's estimated that tens of millions of the stinging creatures that have found a home in New Jersey's largest estuary, Barnegat Bay.
Swimming becomes impossible at times, and some homeowners even say they've lost rentals because of the infestation.
"You don't feel it right away, but then it comes in and it's like a pulsing," said Audrey Hertsberg, a high school student in Montclair, N.J., who has been stung and is working down the shore with scientists from Montclair State University.
The first surge in jellyfish, or sea nettles, as they're more commonly called, was noticed five or six years ago.
Since then, it has been like a series of tsunamis continually pounding the most popular swimming and boating waters in this crowded state.
"Female sea nettles, when they mature, supposedly can put out 40,000 eggs per day," said Jack Gaynor, a Montclair State University biologist who is part of a research team studying what has become a first-class pest.
But Gaynor went on to describe how the jellyfish polyps can then turn asexual; each one can reproduce by the dozens.
From that, he offered an estimate of tens of millions of the unattractive creatures inhabiting Barnegat Bay this summer.
And it gets worse.
In the polyp stage, the jellyfish like to find hard surfaces to grow on.
The development of thousands of homes on the shores of the bay gives them exactly that, in the form of plastic floats supporting docks for all of those homes.
Throw in nitrogen runoff from fertilizing lawns upstream, along with the nitrogen that comes from burning fossil fuels in automobiles and coal-powered electric plants, and the bay's entire ecosystem is upended.
That nitrogen causes algae blooms that suck oxygen out of the water when they die and are eaten by bacteria.
Predator fish die off, leaving the bay to the sea nettles, which can easily exist in low-oxygen water environments, according to Paul Bologna, Montclair State's Director of Aquatic and Coastal Sciences.
"Jellyfish globally are increasing because we've eliminated their predators," Bologna explained. "We've provided environmental conditions that allow them to flourish."
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