No harmful algal blooms in Lake Tahoe, but the public should be aware | South of Lake Tahoe


SOUTH LAKE TAHOE, Calif. — While there may be seaweed “warning” signs on two beaches in South Lake Tahoe, the Lahontan Water Board says they serve only to raise awareness and that no Harmful Algal Bloom (HAB) was not detected there, or at any time. area of ​​water in the Lake Tahoe basin.

Kiva Beach and Connelly Beach both have signage, and there is some visual appearance of algal blooms in these areas, so Lahontan posts the signs due to the high level of recreation that occurs at these beaches.

Lahontan staff sample locations around Lake Tahoe and the Sierra before Memorial Day, July 4 and Labor Day, then if blooms are reported, they will sample those areas as soon as possible according to Sabrina Rice, a scientist at the environment with the Lahontan Regional Water Quality Control Commission. Rice is responsible for the HAB program in the region.

Not all algae is harmful, but understanding what to do will alleviate some concerns. There are thousands of species of algae; most are beneficial and only a few produce toxins or have other harmful effects

Blue-green algae (also called cyanobacteria) are non-pathogenic photosynthetic bacteria that thrive in outdoor bodies of water and produce toxins such as microcystins, cylindrospermopsin, and anatoxin-a. They can grow rapidly and form large blooms, especially in hot weather, and form Harmful Algal Blooms of Toxic Cyanobacteria (CyanoHAB).

Cyanobacteria live in almost all terrestrial and aquatic habitats. Some cyanobacteria are capable of producing a variety of toxins, such as neurotoxins, hepatotoxins, cytotoxins, and endotoxins.

Sometimes the flower is easily visible, forming a “scum” or discoloration on the surface of the water. Other times it is less visible, floating below the surface or at the bottom of a body of water (benthic). The flowers can appear green, blue, yellow, red or brown. Cyanotoxins, produced by cyanobacteria, cannot be detected visually in water or tissue. Several guidance documents are available to aid in the identification of algae and cyanobacteria (Fact Sheet & SOP – Bloom Observation Guide – Google Docs), and the California Freshwater HAB Field Guide is available to aid in monitoring.

People can report the blooms by calling (844) 729-6466 or emailing A freshwater efflorescence incident form is also available on the My Water Quality HAB portal.

There is a map of California with detections and HAB status. The HAB incident report map is managed by the National Water Resources Control Board. This map and corresponding table only show locations where harmful algal blooms (HABs) have been intentionally reported.

Indian Creek Reservoir in Alpine County has a “Danger” rating on the map due to toxicity levels found there in late June.

Algal Bloom FAQs
Visual indicators of a HAB versus non-toxic algae and plants
Council of State Twitter page – some of the most recent HAB information is published via this account

Healthy water habits

If you notice a possible harmful algae bloom, there are steps you can take to protect yourself, your family and your pets. There’s no way to tell if an algal bloom is toxic just by looking at it. The California Water Boards recommend that you practice healthy habits while enjoying the outdoors by your local lake, river, or stream.

Consider all instructions on posted notices, if any
Avoid seaweed and scum in the water and on the shore
Supervise children and pets (dogs)
If you suspect a HAB is present, do not allow pets and other animals to enter or drink the water, or eat scum and algae buildup on the shore
If you suspect a HAB is present, reduce the risk of inhaling sprays or mists by avoiding areas downwind of the bloom and activities near the bloom that could cause sprays, such as boating high speed, water skiing or splashing.
Do not drink the water or use it for cooking
Wash yourself, your family and your pets with clean water after playing water
If you catch fish, discard the casings and clean the fillets with tap water or bottled water before cooking.
Avoid eating shellfish if you suspect a HAB is present

Information specific to dog owners

Dog owners should be aware of HABs just as they are aware of other potential hazards or hazards (such as poison ivy, rattlesnakes, mountain lions, etc.) when outdoors with their dogs.

Bring bottled water with you to give your dog a drink. If in doubt, stay out. But don’t be afraid to be outdoors. Enjoy the outdoors and just be aware.

If your pet enters the water with a flower, wash it immediately with clean water and do not let it lick its fur.

If your pet exhibits symptoms such as convulsions, vomiting, or diarrhea after contact with surface water, contact your veterinarian immediately. Animals and livestock can become very sick and die after being exposed to harmful algal blooms.

Provide your veterinarian with this fact sheet to help identify cyanotoxin illnesses.

Limited funding is available to cover the physical examination of sick dogs suspected of poisoning and other laboratory tests.

See more HERE.


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