- A dog tragically died after exposure to blue-green algae following a swim at one of Lake Tahoe’s beaches.
- Lake Tahoe, especially in Carson City, Douglas, and Washoe Counties, is under HAB Watch due to the likelihood of harmful blue-green algae being present.
- Other water bodies, like Virginia Lake and the Lahontan Reservoir, are also being monitored.
- A veterinarian confirmed, and the final autopsy showed, that Cora ingested neurotoxins from blue-green algae.
Update: Unexpected Findings from Blue-green Algae Bloom Tests in Lake Tahoe are Out
Why Are People Talking About This?
This is Virginia Lake (image from https://ndep.nv.gov/)
There has been a lot of discussion about harmful algal blooms in various parts of Nevada, intensified by a sad story shared on social media.
According to a TikTok video, a woman’s dog, Cora, fell ill and tragically died after swimming at one of the popular beaches in Lake Tahoe.
A veterinarian later confirmed that the cause was neurotoxins from blue-green algae.
Water Test Result
Between July 8 and 10, samples from El Dorado Beach and Nevada Beach were collected and tested for harmful algal blooms (HABs) by the California Interagency Harmful Algal Bloom-related Illness Team.
These locations were selected based on detailed interviews with the reporting party.
Although the results were negative for HAB toxins or blue-green algae, the timing of sample collection could have impacted the findings.
Cora’s owner, Anais Felt, shared on TikTok that Cora died shortly after ingesting toxic algae at El Dorado Beach.
Subsequent water samples collected by the Lahontan Regional Water Quality Board and the Nevada Division of Environmental Protection showed no cyanotoxins at the time.
However, after a thorough review, agencies concluded that Cora’s death met the CDC’s criteria for an algal bloom-associated case.
Felt explained in an interview with News 4 that while the initial water results showed no cyanotoxins, cyanobacteria were present, and these bacteria can quickly become toxic under certain conditions such as heat, which was prevalent during a heat wave when Cora was in the water.
Here’s a helpful guide you might want to read when swimming in Lake Tahoe.
What is a Blue-green Algae?
Blue-green algae, also known as cyanobacteria, are tiny organisms that have been living in water bodies for over a billion years.
They can multiply quickly under the right conditions, creating what we call harmful algal blooms (HABs).
These blooms can sometimes make the water look discolored, form scum, or create mats on the surface.
While most of these blooms are harmless, some types of cyanobacteria can produce toxins harmful to people and animals.
A bloom can be non-toxic one day and toxic the next, which is why it’s always a good idea to avoid any water that looks suspicious.
While blue-green algae are primarily found in freshwater, harmful algal blooms can occur in both freshwater and saltwater environments.
When visiting beaches or saltwater bodies, it’s crucial to check for any advisories or signs of harmful algal blooms.
What Causes These Blooms?
Several factors can contribute to the formation of cyanobacterial blooms, including:
- Warm water temperatures
- Lots of sunlight
- Changes in water flow
- Nutrient levels (like nitrogen and phosphorus)
These conditions often occur in the late summer and early fall, making it more likely for blooms to form during these times.
Current Situation in Nevada
Lake Tahoe, along with other water bodies in Nevada such as Virginia Lake and the Lahontan Reservoir, is being closely monitored in several counties, including Carson City, Washoe, and Douglas.
While these lakes are more likely to have the presence of algae, the situation remains under control with regular monitoring.
Algal Bloom Advisory for Lake Tahoe Beaches
Some parts of Lake Tahoe are currently free from harmful algal blooms (HABs), making it generally safe for swimming and other recreational activities.
However, lakes and reservoirs in counties like Washoe, Carson City, and Douglas are still under monitoring, so it’s best to avoid these areas.
Additionally, some beaches around the lake have “caution” advisory signs due to the potential presence of algae.
Beaches with Advisory Signs
- South Shore:
- Barton Beach
- Connolly Beach
- Tahoe Keys Lagoon (Slalom Court and Traverse)
- North Shore:
- Dollar Creek Reservoir/Bike Path
Specific Findings
- Regan Beach and El Dorado Beach: Samples taken from these beaches detected low levels of Anatoxin-a, prompting caution advisories. The signs warn visitors to stay away from algae and scum in the water and to keep pets and children out of the affected areas. Follow-up testing is conducted to monitor the situation.
- Tahoe Keys: The lagoons in the Tahoe Keys have experienced harmful algal blooms in the past, and recent lab results have sometimes indicated high toxin levels. Monitoring and additional sampling are ongoing to ensure public safety.
How to Stay Safe
If you’re visiting other lakes or reservoirs in Nevada, look out for signs of HABs:
- Water that smells bad
- Floating mats or scums
- Water that looks like green paint or has bright colors like blue, green, or red
- Test the water with the harmful blooms test kits
Even if the water looks clear, it’s always best to check the latest advisories. You can do this by visiting the Nevada HAB Dashboard on the Office of State Epidemiology website for up-to-date information.
For more information, visit the HABs Resources webpage.
FAQs
Q: Are all algal blooms harmful?
A: No, most algal blooms are harmless. However, some types of cyanobacteria can produce toxins that are harmful to humans and animals.
Q: Is Lake Tahoe safe from harmful algal blooms?
A: There are parts of Lake Tahoe in Carson City, Douglas, and Washoe Counties are likely for these algaes to be present.
Q: Which lakes in Nevada and California are currently being monitored for HABs?
A: Virginia Lake, Lahontan Reservoir, Washoe Lake, Carson Lake, Douglas County Lake and Washoe Reservoir are being monitored, and advisories have been issued when necessary.
Q: How can I stay safe from HABs?
A: Avoid water that smells bad, has floating mats, or is discolored. Always check the latest advisories on the Nevada HAB Dashboard before visiting water bodies.
My husband and I love to fish at Lake Tahoe and Pyramid Lake, and we can often be found taking visiting friends and family on boat trips around the lakes.
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