CHIMACUM — Anderson Lake was closed Thursday to fishing and all other water recreation because of high levels of toxin created by blue-green algae.
“The signs are out. The lake is closed until further notice,” said Mike Zimmerman, the ranger who supervises Anderson Lake State Park.
The park remains open to recreation; only the lake is closed.
The most recent tests of water samples found an unsafe level of anatoxin-a, a nerve poison that can kill within four minutes of ingestion.
The popular trout-fishing lake had been open for only two weeks, since April 26, the beginning of the state lowland lakes fishing season.
It historically has had very high levels of anatoxin-a. Last year, the lake between Port Townsend and Chimacum opened in late April, then was closed May 17 because of the toxin level.
“I was surprised it went this quickly, especially given the weather,” Zimmerman said.
“I did hear of a lot of excellent-sized fish” being caught in the lake, he added.
Researchers don’t know what causes certain species of blue-green algae, which occurs naturally and usually is benign, to suddenly begin producing toxins.
They do know toxin levels can rise in the summer because the warmth fuels algae growth when sufficient nutrients such as phosphates are present.
The next test will be next week.
“We’ll keep our fingers crossed and see if we can open again,” Zimmerman said.
