Officials tell Eyewitness News that another 50 to 60 jellyfish were found over the weekend.
Word comes a week after Monmouth Beach issued an alert that the potentially dangerous clinging jellyfish were found in the Shrewsbury River.
A Middletown man swimming in the river had been hospitalized after being stung by one. He needed to be treated with morphine for three days.
The dime-sized species also began appearing in Barnegat Bay, about 45 minutes to the south.
The invasive jellyfish are native to the Pacific Ocean and pack an intensely painful sting.
A brush with multiple clinging jellyfish could possibly lead the victim to a hospital emergency room visit with kidney failure.
"Small things can pack a powerful punch affiliated with their venom and their toxin," said Paul Bologna, the Director of Aquatic Science, Montclair State University.
Scientists aren't sure how the clinging jellyfish have gotten to this area, but they do have a theory.
"A species like this probably was transported via some ship at some point and the larvae came into the system," Bologna said.
The jellyfish have also been spotted in the waters of Cape Cod and Long Island Sound.
Clinging jellyfish hang on to eelgrass or seaweed and usually remain in deep water during the day and surface at night to feed.
They also usually live in bay water.