MONTCLAIR, N.J. (CBSNewYork) — This could be a rough summer for bathers at the Jersey shore.

Scientists have confirmed a box jellyfish washed up in Barnegat Bay last fall and could be a harbinger of things to come.

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“It’s a rather nasty jellyfish that can produce a rather painful sting,” Jack Gaynor, an associate professor of biology at Montclair State University, told 1010 WINS. “It’s a much more serious jellyfish than the three common ones that we typically see along the waters of New Jersey.”

Shore residents reported spotting about a half dozen box jellyfish on beaches in Ocean County last year and one in the Manasquan River.

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Scientists say the box jellyfish is exceedingly rare in New Jersey but fear it could reappear when the water warms this year, according to a USA Today report.

The jellyfish have tentacles that fire “threadlike structures into the skin” which deliver venom, Gaynor said.

Those who get stung should wash the area preferably with fresh water, Gaynor said. Anyone who experiences pain, redness and swelling should promptly seek medical attention.

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“It’s best to really, I know it’s hard to do that, but it’s best to really sort of avoid waters at where you see these jellyfish swimming,” Gaynor said.