Recreation and fishing remain limited at Deal Lake because of poisonous algae blooms, a kind of scum that is more than just gross — it's toxic.

An advisory at Fletcher Lake has been lifted after blooms there deteriorated to safe levels. Watch the video above for what to do if you spot a suspicious bloom.

These incidents highlight the ever-present threat to coastal lakes posed by its neighbors: our homes, our roads, our businesses — us, basically.

“All the coastal lakes in Monmouth County are under quite a bit of stress simply because of all the development around them.” said Joel Grimm, environmental health coordinator at the Monmouth County Health Department.

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In 2017, the presence of harmful "algae" blooms, or HABs, has been confirmed in 11 bodies of water in New Jersey, according to state Department of Environmental Protection records.

These blooms are not actually algae, but cyanobacteria — one of the oldest lifeforms on Earth, according to the National Oceanic and Atmospheric Administration.

Some of these microbes can produce toxins that are poisonous to humans and animals that ingest, breathe in or even touch too much of the toxin.

"Algae" problems aren't anything new, especially to New Jersey's coastal lakes, which are polluted by the stormwater that drains into them.

"I was just driving around the lake yesterday," Deal Lake Commission Chairman Ed Brockel told the Asbury Park Press on Tuesday. "I thought the water color was different in different sections.”

Blooms are becoming more common across America, the U.S. Environmental Protection Agency reports.

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New Jersey began tracking HAB reports for the first time in August as part of a new statewide response strategy, according to a spokesman for the state Department of Environmental Protection.

HABs tend to flourish during this time of the year — late summer, early fall — and have been reported in the Shore during years past.

Cyanobacteria is in every body of water, said Michael Haberland, an associate professor at Rutgers who studies these single-celled organisms — sometimes referred to as blue-green algae — in Camden-area lakes.

But cyanobacteria's growth explodes — as does its dangers — when conditions are just right: warm water, lots of sunlight and plenty of nutrition from nitrogen and phosphorous (mostly animal or human waste).

"Basically what you get is a crock pot cooking," Haberland said. "Summer days when the sun is really high overhead these critters are getting a lot of sunlight energy to reproduce, they're getting a lot of nutrients from the water and it only takes a couple, few days like that to get a bloom."

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The answer is to eliminate or lessen some of the sources of pollution that flow into these lakes, bringing nutrient-rich water to hungry bacteria, and to find other ways to disrupt the "crock pot" scenario.

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In deeper lakes, for instance, aeration devices promote circulation — just like in your fish tank at home — and interfere with the stagnant water that algae prefer.

"That has been quite effective on this really nasty lake (Hopkins Pond in Haddonfield) that I work on," Haberland said.

The commissions that independently oversee Deal, Sunset and Wesley lakes are sharing a $735,000 federal Clean Water Act grant that Brockel says will allow them to treat some of the dirtiest stormwater that comes into Deal Lake.

The Deal Lake Commission is hopeful that will be in place before the end of 2020.

For now, the problems with blue-green algae are expected to persist intermittently, at least until cooler temperatures take hold.

“You can fish all you want, (state regulators) just don’t want you eating what you catch,” Brockel said. “I don’t see any reason not to use the lake. It’s like any lake in (New) Jersey, I would wash off after I was done.”

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Russ Zimmer: 732-557-5748, razimmer@app.com