At Shore, jellyfish seek rivers, bays

BAY HEAD, N.J. - Jellyfish are increasingly making their way into bays and rivers on the Jersey Shore, stinging swimmers and chasing some from recreational spots they had used for decades.

While jellyfish have long been a seasonal affliction at ocean beaches, more are now pushing inland. There, the warmer, calmer waters of bays and rivers provide them a nurturing environment.

"The jellyfish population has exploded," said Willie deCamp, chairman of Save Barnegat Bay, an ecological group.

DeCamp said jellyfish started to appear in the bay in sizable numbers about five years ago.

"Because of them, you're seeing less recreational use of waterways and beaches in some spots," deCamp said.

Sea nettles, a type of jellyfish, have taken up residence in the Manasquan River. Lifeguards at beaches in Point Pleasant, in Ocean County, regularly stock their first aid kits with alcohol swabs to apply to stings that young swimmers get there.

Lavallette, also in Ocean County, has seen large populations of jellyfish in the bay for several years.

"When it's cold in the ocean, we like to train in the bay," said Beach Patrol Lt. Joe Caucino. "But you can't when it's full of jellyfish."

Marine biologists say one of the main culprits in the jellyfish migration is an increase in nitrogen in bays and rivers. Most commonly, this comes from residential lawn fertilizers.

When it rains, some of the fertilizer makes its way down storm drains and eventually into the bay and rivers through outfall pipes.

Stinging jellyfish thrive in nitrogen-rich environments.

Other factors include generally warmer, calmer water in bays. Water discharged from the Oyster Creek Nuclear Generating Station in Lacey Township contributes to higher Barnegat Bay temperatures, and higher jellyfish populations, deCamp said.

Jellyfish stings have been reported up and down the Jersey Shore this summer, but cooler waters this week - Manasquan was 61 degrees on Monday - tend to keep them away from ocean beaches.

New York waterways also are seeing larger jellyfish populations this year.

One breed in particular, the lion's mane, showed up about a month ahead of schedule. Biologists blame everything from breeding conditions to climate change for the abundance so early in the season.