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 for some years. This indicates that C-HARM is predicting positive habitat suitability for Pseudo-nitzschia most of the year 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. Bloom probabilities in the Southern California Bight trended high throughout the month, although confined more to the nearshore zone and with higher spatial and temporal variability, increasing in intensity at the end of July. While COVID-19 sampling restrictions continue to hamper our ability to acquire HABMAP observations from piers, we do know that the more toxigenic Pseudo-nitzschia "seriata" size class approached or surpassed the bloom threshold at the Santa Cruz Wharf for most of July, consistent with the high C-HARM bloom probabilities for Monterey Bay. 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, coinciding with very high bloom probability close to shore in the SLO region at the end of July. The only southern California sites where we have observations for all of July are the Santa Monica and Newport Beach Piers. Pseudo-nitzschia spp. were not recorded during weekly sampling at the Santa Monica Pier. In contrast, at Newport Beach Pier, the Pseudo-nitzschia "delicatissima" size class was at or above bloom levels most of the month, while the more toxigenic Pseudo-nitzschia "seriata" size class approached bloom levels at the end of the month. HABMAP samples were either not collected or data are not yet available for Monterey Wharf, Stearns Wharf, and Scripps Pier. The highest abundances of the Pseudo-nitzschia "seriata" size class recorded by the CDPH were located near SLO and Santa Cruz.
Moderate to very high probabilities (60-100%) of particulate DA (pDA) were predicted for most of the California coast throughout July, with greater offshore extent than in previous months. 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, confined closer to shore. Probabilities 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 was a relative hot spot experiencing persistently high pDA probabilities throughout July. While much of the elevated pDA probabilities extended very far offshore, much like in May & June, 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, with local minima near Sonoma and also in the same zone near SLO where the pDA minima occurred. In general, patterns seen in the pDA output were mirrored by the cDA model but also skewed higher or more extreme, with higher maxima and lower minima. The consistently high probabilities for pDA along the central coast and parts of LA in the Bight are consistent with the six California Sea Lion strandings from suspected DA toxicosis reported by The Marine Mammal Center (TMMC) from San Mateo to SLO Counties in July. One California sea lion stranded in the LA area from suspected DA toxicosis at the end of July as reported by the Marine Mammal Care Center of Los Angeles. This is consistent with the C-HARM predictions of high pDA and high cDA in that region. The only available domoic acid measurements from HABMAP during July were collected at Santa Cruz Wharf and indicated no DA at that site, as has been the case for a year or more. This is inconsistent with C-HARM predictions for pDA but largely consistent for cDA in the Monterey Bay area. Measurements of DA are not yet readily available in the Humboldt region for HABMAP, but the pDA and cDA predictions from C-HARM are consistent with the health advisories issued by the CDPH for domoic acid in razor clams in Del Norte and Humboldt Counties.
Alexandrium - CDPH noted that Alexandrium spp. were very abundant in the SLO region, Morro Bay, and Santa Cruz Wharf in July, consistent with similarly high (and alarming) abundances observed by HABMAP at Santa Cruz Wharf and Cal Poly Pier. Subsequent evaluation of saxitoxin in shellfish led the CDPH to issue health advisories for mussels, clams, and whole scallops in San Mateo, San Francisco, Santa Cruz, and Monterey Counties due to the threat of Paralytic Shellfish Poisoning.
*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 five times in the month of July. Molecular probes for toxigenic Pseudo-nitzschia in the "seriata" class are conducted for this site, and was not detected. Alexandrium spp. were not detected above bloom levels at any time during the sampling period. Domoic acid was not detected in the water samples.
The Santa Cruz Wharf shore station is supported by CeNCOOS PI Raphael Kudela at UCSC.
Water samples were collected four times at Cal Poly Pier in the month of July. Pseudo-nitzschia "delicatissima" was detected above bloom levels on July 27th. Alexandrium spp. were 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 four times at Santa Monica Pier in the month of July. Pseudo-nitzschia "delicatissima" and Pseudo-nitzschia "seriata" were not detected in any of the water samples. Alexandrium spp. were detected at low levels on July 27th 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 three times at Newport Beach Pier in July. Pseudo-nitzschia "delicatissima" was detected above bloom levels on July 13th and below bloom levels on July 6th and 20th. Pseudo-nitzschia "seriata" was detected below bloom levels on July 20th and Alexandrium spp. were detected on July 6th. Domoic acid results aren't yet available.
Newport Beach Pier is supported by SCCOOS PI David Caron at USC.
Please note CDPH recently moved to only reporting Pseudo-nitzschia of the seriata complex and not all Pseudo-nitzschia spp. as previously provided.
From 1-31 July 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 37 of the 79 samples. Pseudo-nitzschia 'seriata' was detected at "Present" density levels (using CDPH relative abundance index) or below. Alexandrium spp. were detected in 22 of the 79 samples in the month of July. Alexandrium spp. were detected at "Common" density levels on July 27th at Morro Bay Boat Launch (10% composition) and 30th at Port San Luis, Diablo Cove (10% 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.
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 July 7 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 July 2020.
July strandings due to suspected DA toxicosis occurred in the following counties:
- San Mateo County (TMMC)
- July 29th - adult, female, California Sea Lion
- Monterey County (TMMC)
- July 16th - subadult, male, California Sea Lion
- July 7th - yearling, male, California Sea Lion
- San Luis Obispo (TMMC)
- July 13th - adult, female, California Sea Lion
- July 18th - adult, male, California Sea Lion
- July 22nd - adult, female, California Sea Lion
- Los Angeles County (MMCC-LA)
- July 25th - adult, female, California Sea Lion