State public-health officials Friday issued a voluntary advisory against water contact in Fish Lake due to an outbreak of blue-green algae that potentially can be toxic to people and pets.
The advisory came on the cusp of the busy Fourth of July weekend at the lake off Highway 140 about 30 miles east of Medford in Jackson County.
Water tests confirmed the presence of a cyanobacteria called anabaena flos-aquae, commonly called blue-green algae, at levels just above the threshold that triggers a public-health advisory under protocols of the state Department of Human Services Harmful Algae Bloom Program.
The tainted water was sampled Monday just outside Fish Lake Resort. Water sampled elsewhere on the lake that day tested well within safe thresholds, said Jennifer Ketterman, the program's coordinator.
Anabaena flos-aquae can produce toxins that can be harmful to people or pets if ingested.
The toxins, however, are not necessarily present during or after a bloom, and toxin levels above safety guidelines set by the World Health Organization have never been found in an Oregon lake or reservoir, public-health records show.
Dogs, however, have died each of the past two summers after ingesting water from Umpqua River backwaters that contained toxins produced by anabaena flos-aquae.
Rogue River-Siskiyou National Forest workers began posting advisory signs against water contact Friday as weekend campers funneled into Forest Service campgrounds ringing the lake, as well as the resort, which is fully reserved for the weekend.
Resort owner Jim Blodgett said the algae was not visible from his dock, and he was incensed that state health officials have yet to pinpoint the causes of algae blooms that have plagued Southern Oregon lakes since 2004.
"The economy can't take hits from these things," Blodgett said. "This is ridiculous."
Fish Lake had a similar advisory that lasted 14 days last August.
The state Department of Human Services recommends people and animals avoid swallowing or inhaling water droplets and recommends no skin contact with Fish Lake water.
Public-health officials also advise campers and other Fish Lake visitors that toxins cannot be removed by boiling, filtering or treating the water with camping-style filters.
People who choose to eat fish caught there should remove all fat, skin and organs before cooking because toxins are more likely to collect in those tissues.
Lost Creek Lake on the upper Rogue River also has an algae advisory in place.
Reach reporter Mark Freeman at 541-776-4470, or email at firstname.lastname@example.org.