It's Baaaack: Algae Bloom Returns Lake Hopatcong

HOPATCONG, NJ - The harmful algal bloom that closed down Lake Hopatcong for large chunks of the summer of 2019 has been detected again by the New Jersey Department of Environmental Protection, albeit in smaller amounts.

Last year, the bloom caused the New Jersey Department of Environmental Protection to take the unprecedented step of issuing a lake-wide advisory against entering, or even touching, the water for further notice, just days before the Fourth of July.

This year the latest testing conducted last week shows the presence of a harmful algal bloom in Crescent Cove near Hudson Avenue at the DEP advisory level, as well as advisories at the DEP watch level for Lake Forest Yacht Club, Mount Arlington Beach, and Hopatcong State Park Beach. All other tested areas of the lake remain below any NJDEP alert level threshold.

At the watch level there are cyanobacteria concentrations of 20K - 40K cells/mL. These are suspected or confirmed HABs with potential for allergenic or irritative health effects. Public bathing beaches remain open, but caution should be used during primary contact activities such as swimming. Do not ingest the water, and do not consume fish. Dogs and other pets should not be allowed in the water because they are very sensitive to bacteria and will drink the water or lick it off their fur, officials said.

At the advisory level there are cyanobacteria concentrations above 80K cells/ml or toxins exceeding public health thresholds. These are confirmed HABs with moderate risk of adverse health effects and increased potential for toxins above public health thresholds. Public beaches close and primary contact recreation (swimming) should be avoided. Use caution during secondary contact recreation (boating without water contact). Do not ingest water (people, pets, livestock) and do not consume fish, officials said.

While it's colloquially referred to as algae, what's causing the mess on Lake Hopatcong are really cyanobacteria. Also called blue-green algae, the microscopic organisms can live in any type of water, and feed through photosynthesis. When there's an abundance of nutrients in the water and powerful sunlight, the cyanobacteria overproduce to cause the types of blooms we've been seeing on Lake Hopatcong this month.

An overgrowth of those bacteria can cause cyanotoxins, some of "the most powerful natural poisons known," Mike Haberland, a county agent and an associate professor at Rutgers Cooperative Extension of Camden County and Burlington County told Patch during the outbreak last year.

"You may think you're stronger [than the bacteria], but why would you want to [find out]?" Haberland posed.

If you or your pet become exposed, clean the affected area with fresh water. If you swallowed any, contact your doctor, poison control, or your pet's veterinarian.

Signs of cyanobacteria poisoning in pets include: loss of appetite, loss of energy, vomiting, stumbling and falling, foaming at the mouth, diarrhea, convulsions, excessive drooling, tremors and seizures, or any other unexplained sickness after being in contact with water.

In serious cases of exposure, the cyanobacteria attacks the liver and can kill animals in several hours, Haberland said.

Long term exposure, particularly from drinking, can cause cancers of the liver and bladder, DEP officials said. Any effects can be more severe in vulnerable populations, including children, the eldrly, and the immunocompromised.

This post contains reporting by Katie Kausch.

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