Keep your dogs safe: Toxic algae found in NJ lakes can kill canines

At least six dogs have died in recent weeks after swimming in lakes and ponds containing harmful blue-green algae — the same type of bloom that struck New Jersey’s two largest lakes this summer.

The deaths — three at a North Carolina pond and three at Lady Bird Lake in Austin, Texas — come as a stark reminder that toxin-producing cyanobacteria are not just dangerous for dogs; they can be fatal.

If bacterial concentrations are high, dogs can die within hours of contact, said Rutgers Cooperative Extension Agent Michael Haberland.

Dogs can be exposed to toxins by drinking or having skin contact with the infested water, Haberland said. They can also be poisoned by grooming their fur and paws after swimming.

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Bacteria also wash up on shores as mats or scum, a form enticing — and deadly — to curious canines, according to a brochure produced by New York Sea Grant.

Different algae species have different toxins, but there are two main offenders. Microcystin affects the liver and can lead to vomiting, diarrhea and seizures in dogs. Anatoxin is a neurotoxin that can cause excessive salivation, muscle tremors and difficulty breathing.

Both can eventually kill exposed canines, Haberland said.

The two species can exist in bodies of water simultaneously. That has been the case in New Jersey's Lake Hopatcong and Greenwood Lake, Haberland added.

"The lake isn't limited to one bacteria," he said. "We have those species creating blooms."

Bloom outbreaks are affecting lakes throughout the Mid-Atlantic region this year, springing up in New Jersey, New York, Pennsylvania and Maryland, as well as in North Carolina and Texas, where the dog deaths occurred.

Algae blooms have plagued Lake Hopatcong in Morris County and Greenwood Lake in  Passaic County this summer, prompting advisories against contact with the water.

Signs at both New Jersey lakes warned away swimmers. The New Jersey Department of Environmental Protection reopened some portions of Lake Hopatcong last month. A no-swimming advisory remains in effect for parts of Greenwood Lake.

But dog owners who visited Lady Bird Lake in Texas and a popular North Carolina pond said they didn’t see warning signage or notice the blooms. Blooms can usually be identified by their pea-soup appearance and putrid smell.

"We are now on a mission to put signs at every body of water that can have this deadly bacteria," Melissa Martin, whose dogs died after swimming in the North Carolina pond, wrote in a Facebook post, which has been shared more than 30,000 times.

Environmental authorities in Texas and North Carolina have since issued alerts telling pet owners to keep their animals away from infected or potentially affected waters.

Experts say no pets in New Jersey have died this year, so far.

"We're not aware of any pets getting sick after swimming in the lake," said Lake Hopatcong Foundation spokeswoman Donna Macalle-Holly.

Experts say owners should keep dogs leashed around bodies of water, and if your dog gets into a lake affected by a blue-green algae bloom, rinse it off and call a veterinarian immediately.

Princeton Hydro, the company that tests for near-shore cyanotoxins in Lake Hopatcong, did not find concentration levels that were above the threshold of concern for the state in July, said Fred Lubnow, the company's director of aquatic programs. The company will test again for the toxins this month.

Blue-green algae thrive in warm, still water with elevated nutrient concentrations. They most often cause problems in larger bodies of water that are less likely to spill over dams after rainfall.

The toxins produced by cyanobacteria blooms can cause a wide range of symptoms in humans, from fever and sore throat to mouth blisters and liver damage. When swimming advisories result from blooms, they can affect local economies dependent on lake tourism.

There’s no single cause of blooms, but a common offender is phosphorus, which is deposited in bodies of water when rainfall washes fertilizer into a lake. A pound of phosphorous can generate 1,000 pounds of algae.

Experts say climate change is increasing the frequency, duration and intensity of the blooms. And once a bloom has developed, there’s little that can be done other than testing the water periodically.

The highest cyanobacteria reading in Greenwood Lake registered levels more than 10 times the safe threshold, the DEP said.