UPDATE: Effective Friday, August 23,  the Monmouth County Health Department has lifted the Manasquan Reservoir advisory regarding the presence of harmful algae. Normally permitted recreational activities have resumed without restriction.

HOWELL, NJ — Direct contact with water in the Manasquan Reservoir should be avoided now that state officials have confirmed high levels of harmful algae blooms are present in the 770-acre body of water — a popular recreational site for area residents.

Testing by the N.J. Department of Environmental Protection revealed levels of cyanobacteria that are at or above “New Jersey health advisory guidance,” according to the advisory on the Monmouth County Health Department website.

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“Do not drink or have contact with the water, including swimming, wading and watersports. Fish caught in this water body should not be eaten. Pets and livestock should not contact or drink the water,” the advistory said, adding that boat rentals also have been suspended until further notice.

Cyanobacteria, also called blue-green algae, develops in dense blooms under suitable environmental conditions that include sunlight, hot and calm waters and high nutrients, producing toxins that are danger humans and animals, according to a DEP fact sheet.

Direct contact with the bacteria can cause a skin rash, flu-like symptoms, gastrointestinal disorders, headaches and vomiting. For pets, drinking or swimming in the water could poison the nervous system, causing loss of appetite, loss of energy, vomiting, stumbling and falling, foaming at the mouth, diarrhea, convulsions, excessive drooling, tremors and seizures, according to the federal Centers for Disease Control and Prevention.

It is the same bacteria that has forced the ban of recreational activities at other bodies of water throughout New Jersey, including Lake Hopatcong in Landing, Budd Lake beach in Mount Olive and the lake at Swartswood State Park.

Part of the Manasquan River system, the 4.67 billion gallon water storage reservoir feeds the Manasquan Water Treatment Center, which provides 60 percent of potable water to Brielle, Sea Girt, Spring Lake, Spring Lake Heights and Wall.

Belmar and Lake Como receive its water from New Jersey American Water Co., which operates the Swimming River Water Treatment Plant in Colts Neck and Jumping Brook Water Treatment Plant in Neptune.

When an algae bloom occurs in a source of water, “appropriate adjustments to drinking water treatment are implemented, if necessary,” according to DEP.