TRAIL — Blue-green algae's four-and-a-half-month grip on Lost Creek Lake officially ends Monday when a public-health advisory against water contact here is scheduled to expire.

TRAIL — Blue-green algae's four-and-a-half-month grip on Lost Creek Lake officially ends Monday when a public-health advisory against water contact here is scheduled to expire.

Water samples taken Jan. 12 reveal little or no anabaena flos aque, a potentially toxic form of bacteria that can be harmful to people or pets if ingested or inhaled.

After accounting for the state-recommended, two-week waiting period for any lingering toxins to dissipate naturally, the no-contact signs which have been here since mid-September are set to disappear Monday.

"Finally, we're just about done," said Ron Howard, the Corps' recreation manager at the reservoir along the upper Rogue River.

Reservoir anglers and area businesses joined Howard in collectively bidding adieu to the advisory, which has scared most fall and winter anglers away from the lake.

Though no illnesses have been attributed to the algae here, the specter of getting sick from inhaling water droplets or digesting tainted trout has kept most anglers home.

"The impact's been huge, huge," said Sue Billows, co-owner of Pat's Hand-Tied Flies along the Rogue, just downstream from the Corps' facilities. "There have been a few people going, but very few, and they won't bring any kids.

"If it's going to be lifted Monday, I expect we'll see a lot of people here this weekend, if the weather's good," Billow said.

This algae strain, which is actually a form of bacteria, has been a bane at this and other reservoirs across Oregon this decade.

The greatest danger is when the algae dies and releases neurotoxins that can cause everything from a skin rash and dizziness to rapid death, though documented reactions have been extremely rare in Oregon.

It is most threatening to children and pets, and it congregates most in shallow, stagnant coves and along shorelines.

Under state guidelines, the non-mandatory advisory also recommends that anglers practice catch-and-release fishing until the advisory is lifted.

But Lost Creek Lake is a popular put-and-take trout fishery, so visitors stayed away during the advisory, which was issued two weeks after the traditional Labor Day weekend end to the boating season.

"In the fall and winter, people are out here to fish," Howard says. "But I think our loss to recreation was minimal because of when it happened."

When anglers do return, they likely will find the lake to be quite productive. December and January angling here often is good for trout 16 to 20 inches long. Popular methods include slow trolling with Wedding Ring lures and bank-fishing with PowerBait near the Takelma Boat Ramp, Howard says.

"January's a good time to catch some nice fish up here," Howard says. "You just have to deal with chilly weather."

The advisory is the third for Lost Creek Lake since 2006 and by far the longest. It leaves only Siltcoos Lake with an algae-related public-health advisory in effect. The advisory at Siltcoos, in western Douglas County, was issued Oct. 28.

The reason for the unusual persistence of the Lost Creek Lake bloom is not known, but possible causes range from an increase in natural or artificial levels of nitrogen to a genetic mutation in the algae itself.

Reach reporter Mark Freeman at 776-4470, or e-mail mfreeman@mailtribune.com.