Harmful algal blooms detected in lakes near Yosemite

Local News

MONO COUNTY, Calif. (KSEE/KGPE)- Harmful algal blooms were discovered at multiple locations in Crowley Lake in Mono County prompting a warning to recreational water users to use extra caution.

According to State Water Resources Control Board, a popular site for trout fishing located 45 miles southeast of Yosemite National Park was tested and confirmed to contain harmful algal blooms. Warning signs and danger advisories have been posted in that area to alert visitors of the elevated health risk.

The water samples were located at the Marina and Hilton Creek Drainage on the southern end of the lake near highway 395.

Lab results detected HAB toxins that exceed the Danger trigger level of 20 micrograms per liter near the Hilton Creek drainage, and HAB toxins exceeded the Warning trigger level of 6 micrograms per liter at the Marina.

How dangerous are Harmful Algal Blooms?

HABs produce dermatoxins that can cause skin inflammation, itchy skin, and rashes, as well as gastrointestinal distress if HAB material is swallowed while swimming.

The bloom occurring in the lake is suspended on the water’s surface. Bloom conditions can change rapidly, as the winds and waves move or concentrate the bloom into different regions of the lake. In some areas, the bloom may concentrate and form a film or scum on the water surface. The color of the water may also appear discolored as bright or dark green.

To report a bloom, click here.

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