If you go swimming in the ocean or a back in New Jersey this summer, watch out for jellyfish.

A Lion's Mane Jellyfish (Dan Kitwood, Getty Images)

"The populations of many types of marine life that used to eat jellyfish, like sea turtles, have been decimated, so that's giving the jellies more opportunity to survive," according to the Director of Aquatic and Coastal Sciences at Montclair State University, Dr. Paul Bologna.

He also points out human development has changed our shoreline, and we don't have the wetlands and salt marshes that we used to, so that's providing more open space for jellyfish to grow, develop and expand their populations.

Dr. Bologna says you want to avoid all types of jellyfish, if possible, because they can and will sting you.

"Things like sea nettles are quite annoying, and they can be in very high densities, but their sting really isn't all that bad," he says, "However, things like lion's mane, which is another common type of New Jersey jellyfish, we don't see nearly as many of them, but their stings are extremely painful."

"When you get hit, it's almost immediate, very large pain and you really start to see immediate welts."

He adds jellyfish are in the ocean and they've also been frequently observed in Barnegat Bay, the Navesink and in Great Bay.

And if you have allergic reactions to bee stings, you may also have a severe reaction to jellyfish stings, so Dr. Bologna recommends steering clear of them whenever you can

"While we need to be aware of the jellyfish situation," he says, "we don't need to be scared of going into the water."