Pseudo-nitzschia - C-HARM tells us where conditions are suitable for species of the diatom Pseudo-nitzschia spp. (all size classes) to grow well and where they might be more likely to produce the deadly neurotoxin, domoic acid (DA). In a break from the trend of previous C-HARM predictions which generally showed good habitat suitability for Pseudo-nitzschia spp. throughout the state, predictions in July suggest patchy suitable habitat for Pseudo-nitzschia spp. Northern California is a persistent hot spot throughout the first half of the month, followed by localized hot spots around San Francisco Bay/Half Moon Bay/Monterey Bay and the Pt. Conception area. As the month progresses, the entire coastline, particularly in central and north CA, is increasingly impacted by bloom predictions, although more confined to the nearshore zones of the Southern California Bight where bloom probabilities southeast of the Santa Barbara Channel region were generally low throughout the month. Given ongoing COVID-19 sampling restrictions and delays that continue to hamper our ability to acquire timely HABMAP observations from piers, most but not all piers are currently making data available. While Pseudo-nitzschia was observed at all the pier sites where data were reported in July, bloom levels were only recorded at Newport Beach Pier (P. 'delicatissima' size class) and Cal Poly Pier (both size classes). The Relative Abundance Index (RAI) for the Pseudo-nitzschia "seriata" size class recorded by the California Department of Public Health (CDPH) reached "Abundant" levels (>50%) at two sites in northern CA near the OR border, "Common" levels (10-49%) at Morro Bay and Diablo Cove (San Luis Obispo region, near Cal Poly Pier), and "Present" at various sites near the San Francisco Bay (e.g. Tomales Bay, Greater Farallones National Marine Sanctuary), Seacliff Pier in Monterey Bay, and sites within the Santa Barbara Channel, Santa Monica/Bolsa Chica in LA County, and at Scripps Pier in San Diego County.
Moderate to very high C-HARM probabilities (50-100%) for particulate domoic acid (pDA) were predicted for large sections of the California coastline in July, with notable "hotspots" in offshore parts of central CA and parts of the coast north of the San Francisco Bay, central coast surrounding Monterey Bay, as well as in and around the Santa Barbara Channel and into the Southern CA Bight. Similar patterns were predicted for cellular domoic acid (cDA) risk as those for pDA, although with much lower probabilities in the Santa Barbara Channel and the Bight. Those cDA probabilities intensified to near 100% from Marin/Sonoma County to Monterey Bay by the end of the month and along most of the north Coast (Humboldt and Del Norte Counties). Mammal stranding data corroborate much of these patterns with a total of seven sea lions stranding from potential DA toxicosis along the central coast (San Luis Obispo to Marin Counties) and one additional stranding in Orange County in southern California. HABMAP pDA data are only so far available at Santa Cruz Wharf for July where no DA was detected. No new shellfish warnings or closures associated with DA occurred in July outside of the annual seasonal quarantine for harvesting recreational shellfish and ongoing razor clam advisories in parts of northern California (lifted in Aug 2021).
Alexandrium - CDPH noted that Alexandrium spp. were "Common" in Morro Bay in July and "Present" at many other sites throughout central CA. This is somewhat consistent with HABMAP sampling, which caught some striking spikes in Alexandrium abundance at Santa Cruz Wharf and Cal Poly Pier throughout July. No recreational shellfish advisories related to PSP were issued in July (however, note the PSP advisory for Marin Co. issued on Aug 27th).
*Please note that HABMAP sampling, CDPH sampling, and marine mammal rescues have been greatly reduced in response to COVID-19 safety measures.
**HABMAP sampling resumed after being suspended in March 2020 in accordance with the Governor's stay at home order. However, COVID-19 safety protocols and sampling restrictions may continue to affect operations and delay results.**
Note that data for some stations are not shown because they are not yet recorded in the public HABMAP archive.
Differentiating Pseudo-nitzschia species by light microscopy is difficult. For this reason, Pseudo-nitzschia "seriata" does not refer to an actual species but rather the larger size class of Pseudo-nitzschia, which is generally a more toxigenic group of species. Alternatively, Pseudo-nitzschia "delicatissima" refers to the smaller size class that is generally non-toxigenic. The dashed line on the plots demarcates the 10,000 cells/L "bloom" threshold designated here for Pseudo-nitzschia populations only.
More information and data visualizations on the statewide HAB network and forecasting system can be found on the California HABMAP website and on the SCCOOS Harmful Algal Bloom page.
Santa Cruz Wharf
Four water samples were collected at Santa Cruz Wharf in July. Molecular probes for toxigenic Pseudo-nitzschia in the "seriata" class are conducted for this site, and was detected on July 7 below threshold. Alexandrium spp. were detected three times (July 7, 21, 28). Domoic acid was not detected.
The Santa Cruz Wharf shore station is supported by CeNCOOS PI Raphael Kudela at UCSC.
Cal Poly Pier
Four water samples were collected at Cal Poly Pier in July. Pseudo-nitzschia "delicatissima" was detected once (July 5), above the threshold. Pseudo-nitzschia "seriata" was detected twice (July 5, 12) with the first above the threshold value. Alexandrium spp. were detected twice (July 5, 19). Domoic acid results are not yet available.
Cal Poly Pier shore station is supported by SCCOOS and PIs Ryan Walter and Ally Pasulka at Cal Poly.
Two water samples were collected at Stearns Wharf in July. Pseudo-nitzschia "delicatissima" and Pseudo-nitzschia "seriata" were detected July 5 and 12, both below the bloom threshold. Alexandrium spp. were not detected. Domoic acid results are not yet available.
Stearns Wharf is supported by SCCOOS and PIs Mark Brzezinski and Libe Washburn at UCSB.
Santa Monica Pier
Four water samples were collected at Santa Monica Pier in July. Pseudo-nitzschia "delicatissima" and Pseudo-nitzschia "seriata" were detected three times (July 5, 12, 19), all below the threshold. Alexandrium spp. were detected once on July 26. Domoic acid results are not yet available.
The Santa Monica Pier shore station is supported by SCCOOS and PI Rebecca Shipe at UCLA.
Newport Beach Pier
Four water samples were collected at Newport Beach Pier in July. Pseudo-nitzschia "delicatissima" was detected once on July 26 and was above the threshold. Pseudo-nitzschia "seriata" and Alexandrium spp. were not detected. Domoic acid results are not yet available.
Newport Beach Pier is supported by SCCOOS and PI David Caron at USC.
Scripps Pier water samples are not available for April 2020 through July 2021.
Scripps Pier is supported by SCCOOS and PIs Melissa Carter and Clarissa Anderson at UCSD.
CDPH observations for Pseudo-nitzschia "seriata" and Alexandrium spp.
Please note, starting in July 2019, CDPH moved to only reporting Pseudo-nitzschia of the seriata complex and not all Pseudo-nitzschia spp. as previously provided.
From July 1-31 2021, water samples were collected by volunteers and sent to the California Department of Public Health (CDPH) for analysis. Pseudo-nitzschia "seriata" group was detected in 55 of the 109 samples. Pseudo-nitzschia "seriata" was detected at "Abundant" density levels (using CDPH relative abundance index) once on July 26 (Wilson Creek, 63% composition) and at "Common" density levels on 6 occasions: July 7 (Trinidad Pier, 15% composition), July 9 (Diablo Cove in Port San Luis, 12% composition), July 12 (Morro Bay Boat Launch, 10% composition), July 13 (Hunter Rock, 40% composition), July 19 (Trinidad Pier, 20% composition) and July 23 (Diablo Cove in Port San Luis, 10% composition). Alexandrium spp. were detected in 27 of the 109 samples. Alexandrium spp. were detected at "Common" density levels once on July 12 (Morro Bay Boat Launch, 10% composition) and at "Present" density levels on 9 occasions: July 9 (Diablo Cove in Port San Luis, 1.5% composition), July 11 (Morro Bay, North T-Pier, 2% composition), July 14 (Diablo Cove in Port San Luis, 8% composition), July 19 (Morro Bay Boat Launch, 2% composition), July 20 (Pillar Point Harbor, 4% composition), July 23 (Diablo Cove in Port San Luis, 4% composition), July 24 (GFNMS, Marin Line 4E, 1% composition), July 25 (Pacifica Pier, 2.5% composition) and July 26 (Morro Bay Boat Launch, 2% composition).
You can view an interactive map and data table of CDPH data from January 2019 to present developed by SCCOOS below or you can also view CDPH Toxic Phytoplankton Observations Map with layers of Pseudo-nitzschia and Alexandrium spp. as well as other phytoplankton species observations (in the pop-up windows).
Data are provided by the California Department of Public Health, Environmental Management Branch.
Please email CDPH at Susan.Paulukonis@cdph.ca.gov for any potential marine HAB-related illness in humans.
CDPH and OEHHA Health Advisories
August 11. The California Department of Public Health (CDPH) has lifted the August 2015 shellfish safety notification related to sport-harvested razor clams in Humboldt County.
May 3. The California Department of Public Health (CDPH) has lifted the August 2015 shellfish safety notification related to sport-harvested razor clams in Del Norte County.
April 30. The California Department of Public Health (CDPH) announced the annual quarantine of sport-harvested mussels gathered along the California coast.
For the latest closures and updates, please visit the CDPH Health Advisories page as a central location of information related to CDPH health advisories. Also available is a map showing the current CDPH Recreational Bivalve Shellfish Advisories (see below).
NEWS: The HAB-related illness workgroup has developed a new webpage for marine HAB-related illness tracking work (https://oehha.ca.gov/fish/general-info/marine-harmful-algal-bloom-hab-related-illness-tracking).
Domoic acid (DA) is a potent neurotoxin produced by some diatom species of the genus Pseudo-nitzschia. Species exposed to DA can result in seizures, epilepsy, cardiomyopathy, and death depending upon the ingested dose. DA toxicosis commonly occurs in California Sea Lions (Zalophus californianus), presumably due to a combination of foraging behavior and seasonal movements. The Marine Mammal Center (TMMC), Channel Islands Marine Wildlife Institute (CIMWI), California Wildlife Center (CWC), Marine Mammal Care Center Los Angeles (MMCC-LA), Marine Animal Rescue (MAR), the Pacific Marine Mammal Center (PMMC), and SeaWorld act like an emergency room by working to rescue and rehabilitate sick and injured marine mammals, seabirds, and sea turtles.
Among the six rehabilitation centers we received data for in the month of July, 8 marine mammal strandings presented with symptoms of domoic acid toxicosis.
The CIMWI, CWC, MMCCLA did not record any strandings due to suspected domoic acid in July 2021.
July strandings due to suspected DA toxicosis occurred in the following counties:
- San Luis Obispo (TMMC)
- July 9 - adult, female, California Sea Lion
- July 16 - adult, female, California Sea Lion
- July 19 - adult, female, California Sea Lion
- July 22 - adult, female, California Sea Lion
- July 24 - adult, female, California Sea Lion
- San Mateo (TMMC)
- July 29 - subadult, male, California Sea Lion
- Marin (TMMC)
- July 30 - adult, female, California Sea Lion
- Orange County (PMMC)
- July 30 - adult, female, California Sea Lion