The Lahontan Regional Water Quality Control Board (Water Boards) are urging fisherman and recreational users to stay out of the water at Crowley Lake located in Mono County.

Localized areas of the lake were tested to confirm that the lake
is being impacted by Harmful Algal Blooms (HABs). The lake is posted with a recreational advisory of “DANGER” to alert lake users of the elevated risk. Recreators are encouraged to follow the below guidance until further notice.

Danger
• Stay out of the water until further notice, including watercraft.
• Do not let pets and other animals drink or go into the water, or go near the scum.
• Stay away from scum, and cloudy or discolored water.
• Do not eat fish or shellfish from this water.
• Do not use this water for drinking or cooking. Boiling or filtering will not make the
water safe.

A volunteer citizen monitoring partner noticed visual observations of a potential bloom
while sampling during the Labor Day Pre-Holiday Assessment at Crowley Lake. Sample
results confirmed toxins present at danger level thresholds in a sample collected from
the marina area. Caution level toxins were present at a second sample collected near
the Hilton Creek drainage.

Note that cyanobacteria, a group of organisms that form harmful algal blooms, can
produce potent toxins. Health risks are associated with HABs as they produce
dermatoxins that can cause skin inflammation, which can cause itching skin and rashes,
as well as gastrointestinal distress, headaches, agitation and weakness, or abnormal
breathing if HAB material is swallowed while swimming.

Dogs and children are most susceptible to exposure because of their smaller body size, increased potential to swallow water while swimming, and tendency to stay in the water longer. If you suspect exposure, wash your children and dog immediately. Due to the size and toxicity of the bloom with increasing temperatures and decreased precipitation this time of year, the
bloom may proliferate and alter its potential to produce toxins.