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 domoic acid (DA). The predicted suitable habitat for Pseudo-nitzschia spp. was spread around throughout coastal California from the Santa Barbara Channel to the Oregon border in July, 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 Pseudo-nitzschia in most parts of coastal California, something that is corroborated by the frequent presence of Pseudo-nitzschia species at our pier sites, albeit not always at bloom levels. In general, the central and north coasts and the Santa Barbara Channel exhibited persistently high bloom probabilities. Local minima in Pseudo-nitzschia bloom probabilities occurred in the 20-50 km nearest the coastline throughout the state at various times in the month. Bloom probabilities in the Southern California Bight trended high throughout the month, although confined more to the nearshore zone and with high spatial and temporal variability, similar to the previous month. While COVID-19 sampling restrictions continue to hamper our ability to acquire 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 throughout August. This is both consistent and inconsistent with the C-HARM bloom probabilities at the pixel near the SC Wharf since they were highly variable, bouncing between zero and 100% probability for bloom levels of Pseudo-nitzschia spp. At Cal Poly Pier, the observed abundance of the less toxigenic Pseudo-nitzschia "delicatissima" size class well exceeded bloom levels at the end of July and again at the end of August, corresponding with very high bloom probabilities close to shore in the SLO region in August that was predicted to be more persistent than pier sampling would indicate. The only southern California sites where we have observations available for all of August are Stearns Wharf in Santa Barbara and Santa Monica Pier. The toxigenic group Pseudo-nitzschia 'seriata' exceeded the bloom threshold at the end of August, while neither size class reached bloom levels at Santa Monica Pier in August. The highest abundances of the Pseudo-nitzschia "seriata" size class recorded by the CDPH were located near San Francisco.
Moderate to very high probabilities (60-100%) of particulate DA (pDA) were predicted for most of the California coast throughout August, maintaining the large offshore extent predicted in July. South of the Santa Barbara Channel, pDA was often predicted to well exceed the 500 ng/L threshold but with a patchy distribution throughout the Bight, and as with Pseudo-nitzschia predictions, but those high probabilities extended far offshore as compared to those in July. Probabilities for pDA along the central coast from Carmel to San Luis Obispo County exhibited local minima in the nearshore, sometimes dipping into zero probability of high pDA in the SLO region. The Los Angeles region/San Pedro Basin was a relative hot spot experiencing persistently high pDA probabilities throughout August, as in July. While much of the elevated pDA probabilities extended very far offshore, predicted cellular DA (cDA) risk appeared to be contained in a fairly tight nearshore band for much of the coastline and was consistently high from northern San Luis Obispo County to the Oregon border for the first half of the month, with local minima and a lot of variability from Sonoma County to the Mexican border. The overall take-away is that cDA was persistently high in the North Coast, suggesting a possible issue there. The consistently high probabilities for pDA along the central coast and parts of LA in the Bight are consistent with the three California Sea Lion strandings from suspected DA toxicosis reported by The Marine Mammal Center (TMMC) from San Mateo to SLO Counties in August, and the one California sea lion stranded in the LA area from suspected DA toxicosis at the beginning of August as reported by the Marine Mammal Care Center of Los Angeles (joining the one LA stranding at the end of July). This is consistent with the C-HARM predictions of high pDA and high cDA in those regions. There are no available domoic acid measurements from HABMAP yet available for August.
Alexandrium - CDPH recorded low or zero Alexandrium spp. at all sites sampled in August, consistent with abundances observed by HABMAP at piers, and in stark contrast to the very high abundances observed in July. This led to the lifting of shellfish safety notifications in San Mateo and San Francisco Counties due to the threat of Paralytic Shellfish Poisoning. However, warnings for PSP in mussels remained for Santa Cruz and Monterey Counties.
*Please note that HABMAP sampling, CDPH sampling, and marine mammal rescues have been greatly reduced in response to COVID-19 safety measures.
**HABMAP sampling has been suspended since March 19th in accordance with the Governor's stay at home order to protect the health and well-being of all Californians and to help slow the spread of COVID-19. Cal Poly and Scripps received an exception to continue collecting water samples for the State and are taking the necessary safety measures to protect field personnel. The water samples are being preserved for future analysis by the Caron or Kudela Labs for domoic acid and Brzezinski/UCSB Marine Analytical Labs for macronutrients when it is safe for lab personnel to do so.**
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 3 times in August. Pseudo-nitzschia "seriata" and Alexandrium spp. were not detected during the sampling period. Domoic acid results are not yet available.
Santa Cruz Wharf shore station is supported by CeNCOOS PI's Raphael Kudela at USCS and Jason Smith and Moss Landing Marine Labs.
Water samples were collected four times at Cal Poly Pier in August. Pseudo-nitzschia "delicatissima" was detected above bloom levels on August 3 and 10. Pseudo-nitzschia "seriata" was not detected in any samples. Alexandrium spp. was detected in three of the four water samples. 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 two times at Stearns Wharf Pier in August. Pseudo-nitzschia "delicatissima" was not detected above bloom levels while Pseudo-nitzschia "seriata" was above bloom values on August 3. Alexandrium spp. was detected in one of the two water samples. 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 four times at Santa Monica Pier in August. Pseudo-nitzschia "delicatissima" and Pseudo-nitzschia "seriata" were not detected above bloom levels. Alexandrium spp. was 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.
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 1-31 August 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 47 of the 85 samples. Pseudo-nitzschia 'seriata' was detected at "Common" density levels (using CDPH relative abundance index) on August 30 at Pacifica Pier (15% composition) and at "Present" density levels or below for the remaining samples. Alexandrium spp. was detected in 16 of the 85 samples in the month of August. Alexandrium spp. was detected at "Present" density levels or below.
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
California Department of Public Health (CDPH) annual quarantine of sport-harvest mussels began May 1, 2020. The quarantine is in place to protect the public against poisoning that can lead to serious illness, including coma and death.
On July 1st, CDPH advised consumers not to eat sport-harvested mussels, clams, or whole scallops from San Francisco, San Mateo, Santa Cruz, and Monterey counties. Dangerous levels of paralytic shellfish poisoning (PSP) toxins have been detected in mussels from those four counties. The naturally occurring PSP toxins can cause illness or death in humans.
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).
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 August 4 marine mammal stranding presented with symptoms of domoic acid toxicosis.
The Channel Islands Marine Wildlife Institute (CIMWI), California Wildlife Center (CWC), Marine Animal Rescue (MAR), Pacific Marine Mammal Center and SeaWorld did not record any strandings due to suspected domoic acid in August 2020.
August strandings due to suspected DA toxicosis occurred in the following counties:
- Los Angeles County (MMCC-LA)
- August 8th - adult, female, California Sea Lion
- San Luis Obispo (TMMC)
- August 6th - adult, male, California Sea Lion
- August 27th - adult, female, California Sea Lion
- San Mateo County (TMMC)
- August 29th - adult, male, California Sea Lion