PORT TOWNSEND — Both Anderson and Gibbs lakes remain closed to fishing, boating and swimming, although the latest test of Anderson Lake found it no longer contains a harmful amount of toxin.
Anderson Lake, which is near Chimacum, which is south of Port Townsend, was closed to recreation May 7 because of high levels of anatoxin-a, a nerve poison that can kill within 4 minutes of ingestion.
The state recreational criteria for the toxin — which is created by blue-green algae, also known as cyanobacteria — is 1 microgram per liter.
“The last round of toxin samples from Anderson Lake were below recreational guidelines,” said Michael Dawson, lead environmental health specialist for the Jefferson County Water Quality Program, in an email.
However, the bloom at Anderson Lake, a popular trout-fishing lake, is still dominated by microcystis and anabaena, cyanobacteria species known to sometimes produce toxins.
So Washington State Parks, which oversees Anderson Lake and the state park surrounding it, decided to keep the lake closed for now, Dawson said.
“If the bloom dissipates, that may change, but we have often seen a late season resurgence of cyanobacteria toxins in Anderson Lake,” he said.
The next test will be in September, he added.
The state park remains open for recreation.
Gibbs Lake
Gibbs Lake, a catch-and-release trout lake near Chimacum, also remains closed to recreation.
The county park around it remains open.
The lake was closed early this month because of high levels of the toxin microcystin.
Microcystin, which is produced by blue-green algae, can cause skin irritation, nausea and muscle weakness if touched and liver damage if swallowed over a long period of time.
Gibbs Lake was mentioned in a state Department of Ecology news release last week as one of several lakes with toxic algae blooms in the state.
“Lakes, rivers and Puget Sound are experiencing more intense and widespread algae blooms this summer,” Ecology said.
Warm waters
It added that scientists believe warm water due to the state’s drought is partly to blame.
Warmth increases the growth of blue-green algae, which is usually benign but which can begin to produce toxins.
Researchers do not know what triggers the toxin release.
Algae growth also is fed by nutrients such as phosphorus, which is found in large amounts in Anderson Lake.
“If you see green algae in the water, don’t go into the water,” said Lizbeth Seebacher, an environmental scientist who oversees the state’s freshwater algae control program in conjunction with the state Department of Health.
“A good rule to remember is that if you see scum on the water, don’t swim in it, and don’t let pets swim in or drink the water.”
For more information about Jefferson County lakes, visit http://tinyurl.com/jeffersonlakequality.
Those who see a bloom on a lake are urged to report it to 360-385-9444.
Toxin-producing blue-green algae has not been spotted in Clallam County.
Report algae blooms in Clallam County by phoning 360-417-2258.
For fishing seasons and regulations, see the state Department of Fish and Wildlife website at www.wdfw.wa.gov.