HAB Resources

Page Contents

Report a Bloom

HAB Monitoring Program Overview

Identifying a Harmful Algal Bloom

Monitoring and Sampling Summary and Key Resources

Monitoring and Sampling Operations Flow Chart

Health Advisory Signs and Posting Guidance

Informational Posters and Brochures 

Join the HAB Listserv


HAB Monitoring Program Overview

The Harmful Algal Bloom (HAB) Monitoring Program is implemented by several state agencies under a Memorandum of Understanding (MOU) signed in 2024 (pending), agreeing to carry out the responsibilities and procedures outlined in the HAB Strategic Response Plan (SRP). The SRP describes each agency's responsibilities, issuance of health advisories, HAB response procedures, standard operating procedure, and available resources in detail. 

These agencies include, but are not limited to: 

The task force executes the HAB Monitoring Program goals through regular monitoring, sampling, and interagency communication. Monitoring and sampling consists of visual assessment in the field, desktop analyses of potential HABs, and collecting samples of affected water. Once a HAB presence is verified through monitoring and sampling, NDEP will recommend that the Office of State Epidemiology (OSE) issue a health advisory reflecting the potential health threat level for the impacted water bodies. Monitoring and sampling are typically conducted during warmer summer months. The task force plans to launch a new HAB reporting tool in the near future. In the meantime, please email NDEP's Biological Assesment and Monitoring Branch to report a suspected bloom. 

Identifying a Harmful Algal Bloom

HABs can be easily identifiable, forming an apparent “scum” or discoloration on the water surface. Some types of algae do not produce harmful cyanotoxins, and differentiating between the two is a helpful skill when monitoring and/or recreating near a surface water body.

HABs can appear green, blue-green, green-brown, or red and can take on a handful of forms. HABs may cause water to look like paint or pea-soup, form scum, bubbling, or spit-like foam, or resemble lettuce or chopped grass (Figure 1). HABs can also have a distinctive smell that can be fishy, rotten, or gasoline-like. If you think you have observed a HAB or suspect a HAB-related illness, please report a suspected bloom.

Figure 1. Harmful algal bloom.

Non-toxic algae and plants are typically green in color but can turn yellow or brown as they decompose. They appear as rooted plants, floating plants, plant-like algae, or filamentous algae (Figure 2). Algae and aquatic plants typically have an earthy, leafy, or neutral odor, but can smell musty or rotten when dying. 

Figure 2. Filamentous green algae (non-toxic algae).


Monitoring and Sampling Summary and Key Resources

 Recommended Actions and Resources
Step 1: Surveillance and General Awareness

Participating agencies (NDEP, DNSP, NDOW, NDA) should visually monitor public waterbodies for potential HABs during recreation season. 

Responding agencies can use general awareness signs to inform the public about HABs.


Step 2: Reporting the Discover of a Potential HAB

Reports of potential HABs should be made through the HAB reporting tool (coming soon), and any potentially related human or animal illnesses should be made to NDHHS, NDA, or NDEP: 

  • Report a potential HAB (link)
  • Human Illness (NDHHS): 1-775-400-0333
  • Animal Illness (NDA): 1-775-738-8076
  • Spill Hotline (NDEP): 1-888-331-6337

NDEP staff will evaluate reported HABs and deploy sampling and health advisories as appropriate. 


Step 3: Interagency Responses, Coordination and Communication

NDEP will evaluate reported potential HABs and coordinate with the appropriate agency staff in responding to the HAB. When potential HAB-related human or animal illness are reported, OSE staff will follow up to collect additional information and provide assisstance. 


Step 4: Field Screening

Responding agency staff can use field screening methods to determine if cyanobacteria and cyanotoxin indicators are present. As necessary, samples may be collected for lab analysis at this step (refer to Step 5). 

Field screening methods includes visual indicators, jar test, and stick test. If field screening methods confirm the presence of HAB indicators or a HAB-related illness is suspected, NDEP will submit a recommendation for a HAB Watch advisory and corresponding advisory signage to be posted at the waterbody to inform recreationalists of potential health risks. 


Step 5: Cyanotoxin Sampling

If field screening methods confirm the presence of HAB indicators or a HAB-related illness is suspected, NDEP will recommend cyanotoxin sampling. NDEP will coordinate with responding agency staff to collect cyanotoxin samples for submittal to NDEP. 


Step 6: Issuing Health Advisories

If analyses or observations meet or exceed Health Advisory Threshold Levels, NDEP will submit a recommendation to the OSE to issue the apporpriate health advisory. NDEP will recommened the corresponding advisory signage to be posted, and will communicate and coordinate with the appropriate agencies. 


Step 7: Continue Monitoring and Revise Advisory as Needed

While a waterbody is under an advisory, ongoing visual monitoring and field screening will be conducted by the responding agency. If observations suggest that the HAB is significantly increasing or decreasing, then the responding agency will communicate with NDEP to determine wether follow-up cyanotoxin samples should be collected. If follow-up cyanotoxin samples are collected, NDEP will submit a reccomendation to OSE to revise the advisory as needed. 


Step 8: Remove Advisories and Routine Monitoring

Once visual indicators and/or cyanotoxin concentrations are below the Health Advisory Threshold Levels for a minimum of two consecutive weeks, NDEP will submit a recommendation to OSE to remove the health advisory signage. 


Monitoring and Sampling Flow Chart

Figure 3. Monitoring and sampling operations flow chart. 

Health Advisory Signs and Posting Guidance

Health advisories can be issued based on visual confirmation, satellite imaging confirmation, and/or laboratory analysis of cyanotoxin concentrations. The level of health advisory is determined by how the HAB is verified and the level of cyanotoxins found in water samples (Table 1). The presence of HABs and related data will be shared with participating agencies as well as the public. The OSE will issue or lift health advisories and encourage field staff to share this information by posting the provided health advisory signage. 

Table 1: Recreational Advisory and Action Levels for Cyanobacteria and Cyanotoxins


For more information on the most recent data and advisories please visit the HAB Data webpage and the HAB OSE Dashboard.


Informational Documents, Posters and Brochures

Report a Bloom

Report a possible bloom to the Biological Assessment and Monitoring Branch

Join the HAB Listserv!

For weekly updates on HAB data and health advisories, please join the Nevada HABs e-mail list by navigating to the bottom of this webpage and clicking "Get Notices" and selecting "Nevada Harmful Algal Bloom Updates" from the dropdown menu, or by sending an e-mail directly to NEVADAHABS-subscribe-request@LISTSERV.STATE.NV.US









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