CHIMACUM — Anderson Lake, which has been plagued with high levels of algae-produced toxins for the past seven years, has been closed to fishing and other recreation after only three weeks.
The popular trout-fishing lake between Port Townsend and Chimacum was opened April 27 for the start of the statewide lowland lake fishing season but was closed to all recreation last week because of high levels of the potent nerve toxin anatoxin-a.
Anatoxin-a
The toxin, which is produced by blue-green algae, was detected in water samples taken Monday from Anderson Lake, said Mike Dawson, water quality lead with the Jefferson County Public Health Department, after results were received from King County Environmental Lab on Friday.
Upon the county’s recommendation, State Parks Ranger Mike Zimmerman closed the lake to fishing, boating and swimming. People also are urged to keep pets out of the water.
The 410-acre Anderson Lake State Park around the lake remains open for hiking, biking and horseback riding.
“Visitors should be aware that the algae bloom at Anderson Lake is not very visible right now,” Dawson said.
“But don’t be fooled by the lack of a bright green scum; the toxin level is high.”
Toxin level climbs
The toxin level in Anderson Lake was found to have climbed to 4.26 micrograms per liter, which is more than four times greater than the safety threshold of 1 microgram per liter, Dawson said.
Anatoxin-a is produced by blue-green algae, also known as cyanobacteria, which occurs naturally but which can begin, for unknown reasons, to produce toxins.
It is a quick-acting poison that can lead to death in people and animals within four minutes if ingested in high doses.
The county public health department has seasonally monitored area lakes for blue-green algae since two dogs died after lapping water from the lake on Memorial Day weekend in 2006.
Monthly monitoring
Monthly monitoring of Anderson, Gibbs and Leland lakes in East Jefferson County began in April of this year, with weekly toxin samples taken when blooms are present, Dawson said.
No microcystin was detected in Anderson Lake. Microcystin can cause skin irritation, nausea and muscle weakness if touched and liver damage if swallowed over a long period of time.
Gibbs Lake, south of Port Townsend, and Lake Leland , north of Quilcene, have had light blooms but only low levels of toxins so far in 2013, he added, saying that caution signs are up at Gibbs and Leland.
Researchers don’t know why some types of algae will suddenly begin producing toxins.
They know only that warmer weather and longer days tend to fuel the growth of blue-green algae when the lake contains enough nutrients, such as phosphorus.
Visitors need a Discover Pass — either $10 for a day or $30 for a year — to park within Anderson Lake State Park.
Discover Pass
Passes can be bought at any state park, where hunting or fishing licenses are sold, by phoning 866-320-9933 or by visiting www.discoverpass.wa.gov.
Toxin-producing blue-green algae has not been spotted in Clallam County.
Report algae blooms in Clallam County by phoning 360-417-2258, while Jefferson County blooms can be reported at 360-385-9444.
For more information about Jefferson County lakes, visit http://tinyurl.com/jeffersonlakequality or phone the office.
For fishing seasons and regulations, visit the state Department of Fish and Wildlife website at www.wdfw.wa.gov/fishing.
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Managing Editor/News Leah Leach can be reached at 360-417-3531 or at leah.leach@peninsuladailynews.com.
