Be sure to also read the special Red Tide Bulletin: Spring 2020
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). The predicted suitable habitat for Pseudo-nitzschia spp. was spread throughout coastal California from the Santa Barbara Channel to the Oregon border in November, a pattern in the C-HARM model that has persisted but with some nuances each month. This indicates that C-HARM is predicting positive habitat suitability for the genus Pseudo-nitzschia in most parts of coastal California much of the time, something that is corroborated by the frequent presence of Pseudo-nitzschia species at our pier sites, albeit not always at bloom levels. The model may or may not be overpredicting bloom levels offshore, but this is hard to know without validation data in those areas away from where we routinely measure (e.g. piers). In general, in November the entire coast exhibits persistently high bloom probabilities, with a little more variability in Southern California, as was the case the month prior. While COVID-19 sampling restrictions continue to hamper our ability to acquire timely HABMAP observations from piers, we do know that the abundance of the toxigenic Pseudo-nitzschia "seriata" size class remained at zero at Santa Cruz Wharf, as it has been since July. This is both consistent and inconsistent with the C-HARM bloom probabilities at the pixel near the SC Wharf since they were variable, bouncing between zero and 100% probability for bloom levels of Pseudo-nitzschia spp., albeit with less variability than in September and October. At Cal Poly Pier, the observed abundance of both Pseudo-nitzschia size classes showed some uptick in September and October and then finally reached "operational" bloom levels by mid/late November, consistent with the more persistently high probabilities for Pseudo-nitzschia bloom risk in San Luis Obispo nearing the end of the month. In the Southern California Bight, bloom levels were observed in mid/late November at Stearns Wharf and Newport Beach Pier, for both Pseudo-nitzschia size classes (noting that data are not yet available for Scripps Pier due to COVID19-related delays and personnel challenges). The Relative Abundance Index (RAI) for the Pseudo-nitzschia 'seriata' size class recorded by the CDPH was quite high at sites within SF and Tomales Bays and moderately high in areas outside the Golden Gate, such as Pacifica.
Moderate to very high C-HARM probabilities (50-100%) for particulate DA (pDA) were predicted at different times for several sections of the California coastline in November. Notable hotspots from south to north were: San Diego and Orange County regions (mid-late Nov), the Santa Barbara Channel (particularly the western Channel, mid-month), San Luis Obispo region (late Nov), Monterey Bay (mid-month), SF and Marin Counties (much of the month), Sonoma Co. (mid-month), North Coastal region (particularly Humboldt/Del Norte Counties, most of the month, with a greater offshore extent than other regions). No particulate domoic acid was measured at the two HABMAP sites for which November DA data are so far available (SC Wharf and Newport Beach Pier). Similar patterns were predicted for cellular DA (cDA) risk. Hotspots from south to north were: San Diego and Orange County regions (mid-late Nov), the Santa Barbara Channel (particularly the western Channel, mid-month, and southern side of the islands in late Nov), San Luis Obispo region (late Nov), Monterey Bay (probabilities somewhat elevated at the end of the month), SF and Marin Counties (much of the month), Sonoma Co. (mid to late Nov), North Coastal region (particularly Humboldt/Del Norte Counties, most of the month, with a greater offshore extent than other regions). The overall take-away this entire fall has been that cDA probabilities were frequently high along the North and Sonoma Coasts (including areas adjacent to SF Bay), suggesting a possible issue there for domoic acid. The very high probabilities for pDA (and cDA) near SF Bay were consistent with the two California Sea Lion strandings from suspected DA toxicosis reported by The Marine Mammal Center (TMMC) from Marin in early Nov and San Francisco in mid-Nov. Two suspected toxicosis strandings were reported for Santa Cruz in early and late November, an area that was predicted to have highly variable risk for toxins and no measured domoic acid at SC Wharf on the one recorded sampling day in mid-Nov. Either those animals acquired the toxin further offshore of the Monterey Bay (where pDA and cDA probabilities were notably higher) or in the subsurface zone not represented by C-HARM and not measured at the relatively shallow SC Wharf. There were no sea lion strandings from suspected DA toxicosis reported by rescue groups south of Monterey Bay in November.
Alexandrium - CDPH observed Alexandrium spp. at many sites sampled in November, and while RAI was not particularly high at any site, PSP toxins were detected by the state at dangerous levels in wild-caught shellfish at the end of October in Sonoma County, prompting a helth adivsory. Health Advisories were also issued mid-November for Mendocino and Humboldt Counties due to elevated PSP toxins in wild-caught shellfish, warning consumers not to eat recreationally harvested bivalve shellfish.
*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 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.
Water samples were collected at Santa Cruz Wharf 4 times in November. Molecular probes for toxigenic Pseudo-nitzschia in the "seriata" class are conducted for this site, and was not detected. Alexandrium spp. were detected twice (Nov 3, 10).
The Santa Cruz Wharf shore station is supported by CeNCOOS PI Raphael Kudela at UCSC.
Water samples were collected 5 times at Cal Poly Pier in November. Pseudo-nitzschia "delicatissima" was detected in each sample. Values were above bloom thresholds on Nov 16, 23, 30. Pseudo-nitzschia "seriata" was detected in all but one sample, and 2 samples were above bloom thresholds (Nov 23, 30). Alexandrium spp. were not detected and domoic acid results are not yet available.
Cal Poly Pier shore station is supported by SCCOOS PI Ryan Walter and Ally Pasulka at Cal Poly.
Water samples were collected 3 times at Stearns Wharf in November. Pseudo-nitzschia "delicatissima" was detected in 2 samples below bloom levels. Pseudo-nitzschia "seriata" was also detected in 2 samples with only Nov 17 above bloom levels. Alexandrium spp. were detected in one sample and domoic acid results are not yet available.
Stearns Wharf is supported by SCCOOS PI Mark Brzezinski and Libe Washburn at UCSB.
Water samples were collected 5 times at Santa Monica Pier in November. Pseudo-nitzschia "delicatissima" was detected in 3 samples with only Nov 23 being above the bloom threshold. Pseudo-nitzschia "seriata" was detected on 3 occasions all below the threshold. Alexandrium spp. were not detected in any samples and domoic acid results are not yet available.
Santa Monica Pier shore station is supported by SCCOOS PI Rebecca Shipe at UCLA.
Water samples were collected 5 times at Newport Beach Pier in November. Pseudo-nitzschia "delicatissima" was detected in 4 samples with 3 being above bloom levels (Nov 2, 9, 16). Pseudo-nitzschia "seriata" was detected in 4 samples with only Nov 9, 16 being above bloom levels. Alexandrium spp. were not detected. Domoic acid wasn't detected in 2 samples with the remaining results pending.
Newport Beach Pier is supported by SCCOOS PI David Caron at USC.
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 1-30 November 2020, 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 59 of the 98 samples. Pseudo-nitzschia 'seriata' was detected at "Common" density levels (using CDPH relative abundance index) on 10 occasions: November 2nd (2 locations in Humboldt Bay, 30% and 40% composition), 3rd (Port Arena, 15%), 9th (Humboldt Bay, 25%), 15th (Tomales Bay, 15%), 16th (Humboldt Bay, 15%), 17th (Imperial Beach, 10%), 21st (Point Dume, 15%), 25th (Imperial Beach, 10%), 29th (Tomales Bay, 20%). Alexandrium spp. were detected in 30 of the 98 samples in the month of November. Alexandrium spp. were detected at "Present" density levels on 4 occasions.
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.
CDPH and OEHHA Health Advisories
November 18. California Department of Public Health (CDPH) is advising consumers not to eat sport-harvested mussels, clams, or whole scallops from Mendocino County due to dangerous levels of paralytic shellfish poisoning (PSP) toxins.
November 12. CDPH is advising consumers not to eat sport-harvested mussels, clams, or whole scallops from Humboldt County due to dangerous levels of paralytic shellfish poisoning (PSP) toxins.
October 30. CDPH announced the statewide annual quarantine on mussels gathered by sport harvesters along the California coast, except for Sonoma County, ends at midnight on Saturday, October 31, 2020. CDPH is advising consumers not to eat sports-harvested mussels, clams, or whole scallops from Sonoma County. Dangerous levels of PSP toxins have been detected in mussels from this area making them unsafe to consume.
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 seven rehabilitation centers we received data for in the month of November 4 marine mammal stranding presented with symptoms of domoic acid toxicosis.
The California Wildlife Center (CWC), Pacific Marine Mammal Center (PMMC), Marine Mammal Care Center Los Angeles (MMCCLA), and SeaWorld did not record any strandings due to suspected domoic acid in November 2020.
November strandings due to suspected DA toxicosis occurred in the following counties:
- Santa Cruz (TMMC)
- November 4 - juvenile, male, California Sea Lion
- November 20 - pup, female, California Sea Lion
- San Francisco (TMMC)
- November 15 - subadult, male, California Sea Lion
- Marin (TMMC)
- November 2 - adult, female, California Sea Lion