Lone Lake is closed temporarily due to toxic algae levels that are nearly 50 times above the provisional recreation limit set by the state.

The lake contained 49.030 micrograms per liter of Anatoxin-a, a neurotoxin also known as the “Very Fast Death Factor,” in a test conducted on July 13. Ingesting enough Anatoxin-a can disrupt the link between nerves and muscles and can lead to loss of coordination, muscular fasciculations, convulsions and death by respiratory paralysis. There were also small amounts of Microcystin found, but it was not above the state guideline.

The toxic algae is visible to the naked eye as a layer of green “scum” on the water, Island County Environmental Health Specialist Maribeth Crandell said. A notice posted on Wednesday by Island County advises people to stay out of the lake and call a doctor or veterinarian if a person or animal is experiencing a sudden or unexplained sickness or signs of poisoning.

The toxic algae bloom may not have a singular cause, but possibly multiple; Crandell said the heat, goose poop, leaky septic systems and the topography of the lake may all have been factors in the county closing the lake temporarily.

The lake has the highest level of toxicity since 2015, when there were 93.100 micrograms per little of Anatoxin-A and 21.100 micrograms of Microcystin. Anatoxin-a levels also exceeded the state limits in July 2016 when there were 10.700 micrograms found.

Algae blooms in the past have been linked to the presence of grass carp, a vegetarian fish that was meant to reduce noxious weed Brazilian elodea. Fishermen wielding bows and arrows began in April and May reducing the population which was once estimated at about 800.

The county utilized data collected from the water by Clyde Jenkins, a member of South Whidbey Yacht Club, who said he used an Abraxis testing kit to examine toxicity levels. He sent the samples from July 13 to a King County lab for more testing, the results of which were sent to Island County and Washington State Toxic Algae, a freshwater algae bloom monitoring program.

Jenkins said he was surprised by the results of the test. He also added that toxicity levels are based on what the toxins could do to someone who is around 33 pounds, which would roughly be the size of a two-year-old for example.

“They are very cautiously set,” Jenkins said.

Jenkins used vials, eye droppers, chemicals from the Abraxis kit to test the samples.

“You let it sit for five or ten minutes and you compare it to a chart,” Jenkins said.

The toxic algae bloom has caused some disruption in sailing classes for the South Whidbey Yacht Club. Bob Rodgers, commodore of the club, said both the beginner and intermediate classes were forced to move to Goss and Deer lakes, respectively. Rodgers said there are few drawbacks to Lone Lake’s closure, such as not being able to use motors on Goss Lake and having a slower response time if a sailor were to get into some trouble.

But, he said the Goss Lake neighbors have been welcoming and receptive to an onslaught of sailors flying around their “usually quiet little lake.” He said they’ve also been fortunate enough to launch from docks owned by private property owners, but it’s not something the club would like to do forever.

Bill Brown, an instructor with the yacht club, was also disappointed by the lake’s closure but understood the necessity. He also said the yacht club has an advantage now that it can test the water for toxicity.

Crandell did not know whether or not the toxic algae is harmful to fish. Langley fisherman Clayton Wright of the Whidbey Fly Fishing Club is hopeful that the lake will not be closed for long and that fishing won’t be impacted. They typically do catch-and-release anyway, he said.

“To us, it’s not a show stopper,” Wright said. “I don’t think it’s going to be a big impact to fishing at this stage.”