Social media users in search of “blue hole” swimming in New Jersey have helped drive an “unprecedented” number of people to the once hidden spots, so named because of the deep color of the water in some New Jersey Pinelands locations associated with old quarries.

Now, officials are cracking down ahead of Memorial Day weekend on the swimming holes that are not officially open to bathers, citing “the unprecedented unauthorized use of several portions of the Wildcat Ridge, Greenwood Forest, Winslow, Cedar Lake, and Menantico Wildlife Management Areas.“

Closure begins immediately and continues through Sept. 15, the state Division of Fish and Wildlife said. Violators faces fines of $50 to $1,500.

State officials said the locations “attract large gatherings and include former quarry pits at which swimming is prohibited and extremely dangerous due to the depth and low temperature of the water which can threaten life and safety.”

Swimming is authorized in New Jersey State Parks only at lifeguarded beaches, officials cautioned.

The blue holes draw swimmers from around the region, and some even have their own social media pages set up by zealous users. However, they are not maintained and there are no lifeguards or facilities.

The water can be 50 to 100 feet deep in some areas. People have drowned at several of the locations over the years.

The spots draw not only swimmers, but also ATVs, boaters, and hikers in search of an Instagram-worthy location. Like many natural areas, they became increasingly popular during the pandemic, leading to complaints about large crowds and the litter they leave behind.

New Jersey’s Wildlife Management Areas were originally funded by hunting and fishing licenses and were intended to preserve habitat. However, with the addition of state Green Acre funds, the areas grew in size and the mission expanded to provide outdoor recreation, complete with boat ramps and parking lots. But they remain more rustic than state parks, and have no receptacles to dispose of trash.

Meanwhile, in Pennsylvania, the Department of Conservation & Natural Resources issued an “extreme crowding” warning for 14 state parks now that an “extraordinary number of people” are causing park officials to turn away visitors. Among the most overcrowded in the Philadelphia area are: Tyler, French Creek, Marsh Creek, Neshaminy, Nockamixon, and Washington Crossing. Officials advise potential visitors to call a park’s office or check its web page before heading out between 9 a.m. and 3 p.m. on weekends, or to look for alternative parks.

In New Jersey, of the Wildlife Management Areas affected by the closures, three are in South Jersey:

  • Cedar Lake WMA: 360 acres off Jackson Road in Monroe Township in Gloucester County and Buena Vista in Atlantic County. The part known as the sand plant is closed, including all property within the boundary beginning at the intersection of Jackson and West Piney Hollow Roads; north on West Piney Hollow Road to Route 322; east on Route 322 to Cains Mill Road; south on Cains Mill Road to Malaga Road; south on Malaga Road to East Reading Avenue; south on East Reading Avenue to Lake Avenue; south on Lake Avenue to Jackson Road; west on Jackson Road to the starting point at West Piney Hollow Road.

  • The Winslow WMA: 8,406 acres wedged between Routes 322, 73, and the Atlantic City Expressway in Winslow Township in Camden County and Monroe Township in Gloucester County. The portion of the WMA known as Winslow East or the Hot Mix section is closed. That includes all property within the boundary beginning at the intersection of Route 322 and Piney Hollow Road; north along Piney Hollow Road to its intersection with Folsom Road (Route 73); southeast on Folsom Road to its intersection with the Camden-Gloucester County boundary; south along the Camden-Gloucester County boundary to its intersection with Route 322; west along Route 322 to the starting point at the intersection with Piney Hollow Road.

  • Menantico Ponds WMA: 474 acres in Millville, Cumberland County, between Routes 55 and 49. All property within the WMA is closed as well as the access road from Route 49.