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 December, 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. The most pronounced change from November is the offshore extent of persistently high bloom probabilities in December. Given ongoing COVID-19 sampling restrictions and delays that continue to hamper our ability to acquire timely HABMAP observations from piers, not all piers are currently providing data but we do know that bloom levels for both the toxigenic and nontoxigenic size class of Pseudo-nitzschia were observed only at Cal Poly Pier in December. The relatively nontoxigenic "delicatissima" size class was elevated at Santa Monica Pier but did not reach operational bloom levels. The Relative Abundance Index (RAI) for the Pseudo-nitzschia 'seriata' size class recorded by the CDPH was quite high in and around San Francisco and Tomales Bays and moderately high in areas outside the Golden Gate, such as Pacifica, a pattern that has persisted since November.

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 December. Notable hotspots from south to north were: San Diego and Orange County regions (mid-late Dec), San Pedro Bay and surroundings, the Santa Barbara Channel (esp south of the islands and in the western channel around Pt Conception), southern San Luis Obispo coast, Monterey Bay (highly variable, mostly southern Bay and regions outside the Bay), Half Moon Bay to SF Bay, and the North Coastal region (north of Pt. Arena and with a much reduced offshore footprint relative to November). No particulate domoic acid was measured at the only HABMAP site for which December DA data are so far available (SC Wharf). Similar patterns were predicted for cellular DA (cDA) risk as those for pDA, although with some notable differences. Hotspots from south to north were: San Diego to LA County regions (mid-late Dec), the Santa Barbara Channel (mid-late Dec), San Luis Obispo region (mid-late Dec), Monterey Bay (probabilities higher than for pDA throughout the month), SF Bay and offshore (much of the month), Marin to Mendocino Co. (mid Dec), North of Pt Arena (most of the month, with a greater offshore extent than for pDA). 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) in these hotspots is consistent with the eight California Sea Lion strandings from suspected DA toxicosis from LA, SLO, SF, Marin, and Mendocino Counties reported by The Marine Mammal Center (TMMC) and Marine Mammal Care Center Los Angeles (MCCLA).

Alexandrium -  CDPH observed very low abundances of Alexandrium spp. at sites sampled in December, consistent with HABMAP sampling. However, at the end of December, CDPH issued a PSP advisory for wild-caught shellfish in Marin County after lifting a similar advisory for Humboldt County.

*Please note that HABMAP sampling, CDPH sampling, and marine mammal rescues have been greatly reduced in response to COVID-19 safety measures.  

Santa Cruz Wharf

Two water samples were collected at Santa Cruz Wharf in December. Molecular probes for toxigenic Pseudo-nitzschia in the "seriata" class are conducted for this site, and was detected below bloom levels. Alexandrium spp. were detected also below bloom levels. Domoic acid results are not yet available.

The Santa Cruz Wharf shore station is supported by CeNCOOS PI Raphael Kudela at UCSC.

Monterey Wharf

Water sampling has been suspended at Monterey Wharf since March 2020 in response to COVID-19 safety measures. 

Monterey Wharf shore station is supported by CeNCOOS PI's Raphael Kudela at USCS and Jason Smith and Moss Landing Marine Labs.

Cal Poly Pier

Water samples were collected 4 times at Cal Poly Pier in December. Pseudo-nitzschia "delicatissima" was detected three times (Dec 7, 14, 21) below bloom threshold values. Pseudo-nitzschia "seriata" was detected once on Dec 7. Alexandrium spp. were not detected in any sample. 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. 

Stearns Wharf

No samples were collected at Stearns Wharf in December.

Stearns Wharf is supported by SCCOOS PI Mark Brzezinski and Libe Washburn at UCSB. 

Santa Monica Pier

Water samples were collected 4 times at Santa Monica Pier in December. Pseudo-nitzschia "delicatissima" and Pseudo-nitzschia "seriata" were detected below bloom levels twice (Dec 21, 28). 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.

Scripps Pier

Scripps Pier water samples are not yet available for April through December 2020. 

Scripps Pier is supported by SCCOOS and PIs Melissa Carter and Clarissa Anderson at UCSD.