Blue-green algae has reared its potentially toxic head again at Lost Creek Lake, triggering a public-health advisory against water contact there just as the summer boating season is kicking in — and four days before a Free Fishing Weekend event there…
The Oregon Health Authority on Tuesday afternoon issued the volunteer advisory — the first this year in Oregon — after the discovery of a large bloom of the cyanobacteria at Jackson County’s largest water body.
Water tests showed more than 3.2 million cells per milliliter of Anabaena flos-aquae, a pest that has bloomed regularly in late spring at the Rogue River reservoir 30 miles north of Medford, according to the U.S. Army Corps of Engineers, which operates the lake.
Anabaena flos-aquae can produce potentially dangerous toxins, particularly when the bloom dies off. But not all blooms become toxic. The threshold for a public-health advisory in Oregon is 100,000 cells per milliliter.
Corps natural resource specialist Justin Stegall said he noticed the algae blooming last week and took water samples Thursday, leading to Tuesday’s advisory — the seventh straight year with at least one algae-related advisory.
“It seems like it came on a little early, and other than that it’s the same green-looking lake,” Stegall said. “Hopefully, it will go away quickly.”
Stewart State Park was set to host a Free Fishing Weekend event Saturday, but that could be canceled, park Manager Perry Silvestrin said just minutes after learning of the advisory Tuesday.
“I haven’t talked with my staff about it,” Silvestrin said. “It’s probably prudent that we shouldn’t go on with it. But I haven’t decided yet.”
Dan VanDyke, the Oregon Department of Fish and Wildlife’s Rogue District fish biologist, said his agency still plans to stock 5,250 legal-sized rainbow trout this week in preparation for Saturday’s event.
“In my opinion, the advisories let people know that the bloom’s there and how to protect themselves when they use the lake,” VanDyke says.
During advisories, people and pets are warned to avoid water contact, but compliance is voluntary. Anglers are encouraged to practice catch-and-release fishing during advisories.
Toxins cannot be filtered by standard camp filters or by boiling the water. In-home filtering systems cannot cleanse the water, though public treatment plants can reduce algae toxins through filtration and disinfection.
People who eat fish from algae-tainted waters should remove all fat, skin and organs before cooking, because toxins can collect there. People should not eat crayfish or freshwater shellfish taken from infested lakes during an advisory.
Boating and fishing are considered safe so long as boat speeds do not create excessive water spray, according to health officials.
Exposure to toxins can produce numbness, tingling and dizziness that can lead to difficulty breathing or heart problems that require immediate medical attention. Symptoms of skin irritation, weakness, diarrhea, nausea, cramps and fainting should also receive medical attention if they persist or worsen.
Children and pets are at increased risk for exposure because of their size and level of activity.
The public will be advised when the concern no longer exists.
Not all blue-green algae strains produce toxins dangerous to people or pets, and not all blooms release toxins.
No confirmed human illnesses have been tied directly to an algae outbreak in Oregon. However, at least four dogs have died in recent years from toxins in water near the Umpqua River near Elkton.
During the past seven years at Lost Creek Lake, spring blooms have typically been shorter than fall blooms.
The longest lasted 134 days in 2008-09. The shortest was 25 days in the summer of 2009, health records show.
Twelve advisories were issued last year in Oregon, including Lost Creek and Willow reservoirs.
The cause of the Lost Creek Lake blooms is unknown, but they have been part of the landscape at the reservoir since Oregon health officials began charting such blooms about a decade ago.
Mark Freeman, Mail Tribune
View original article at: Warning issued over Lost Creek Lake algae bloom