By Kathryn Reed

The cautionary signs that have dotted the canals in the Tahoe Keys are coming down.

“As expected with the seasonal change, the shorter days (less sunlight) and cooler temperatures have helped control the cyanobacteria levels,” Mary Fiore-Wagner with Lahontan Regional Water Quality Control Board told Lake Tahoe News.

The most recent water samples taken Oct. 16 show “non-detectable levels for Anatoxin-a (this is the toxin that domestic pets-dogs) may be especially sensitive too due to increased exposure), and low (below 0.8 ug/L) or non-detect levels for microcystins. Additionally, the TKPOA area is no longer supporting the summer recreationalists entering the Tahoe Keys waterways for both contact and non-contact water recreation, so exposure potential to any cyanotoxins is minimized.”

These numbers are below the mark that necessitate a public advisory.

The blue-green algae was first detected in August. Warning signs were placed throughout the South Lake Tahoe neighborhood. People had been advised not to touch the water, allow dogs to drink it, or to eat the fish from it.

Cyanobacteria blooms can look like slicks of opaque, bright green paint, or “pea soup,” but closer inspection often reveals the grainy, sawdust-like appearance of individual colonies, according to the state Water Board.

Scientists don’t definitively know why-how it is created or how it goes away.

“We did recommend that TKPOA continue routine visual monitoring and one more sampling run within a month’s time to confirm that cyanotoxins have maintained at non-detect and/or insignificant levels that no longer pose a potential risk to human or animal health,” Fiore-Wagner said.