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.  

Santa Cruz Wharf

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.

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 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. 

Stearns Wharf

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. 

Santa Monica Pier

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.

Scripps Pier

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

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