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. in March 2021 suggested widespread suitability throughout the state for Pseudo-nitzschia to grow and reach bloom levels, although the centers of highest likelihood shifted up and down the state throughout the month. The focal point was central California to the Santa Barbara Channel and into the nearshore zones of the Southern California Bight. Generally, though, C-HARM is still 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 in water samples at nearshore sites in most months. 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 the more toxigenic size class of Pseudo-nitzschia was observed at or above the bloom threshold at Santa Cruz Wharf, Cal Poly Pier, Santa Monica Pier, and Newport Beach Pier (where the less toxigenic "delicatissima" size class also bloomed in February and March). This is consistent with the fluctuating loci of high Pseudo-nitzschia probability that were skewed towards central to southern California. The Relative Abundance Index (RAI) for the Pseudo-nitzschia "seriata" size class recorded by the CDPH reached moderate levels (9-15%) in and around San Francisco and Tomales Bays, Santa Cruz Wharf, San Luis Obispo, similar to February. The difference was that sites in the Santa Barbara area and throughout Los Angeles and Orange Counties exhibited lower RAI for Pseudo-nitzschia "seriata" than they did in February, in contrast to the bloom levels seen at southern California pier sites sampled via HABMAP.

Moderate to very high C-HARM probabilities (50-100%) for particulate domoic acid (pDA) were predicted at different times for several sections of the California coastline in March with a focus on the central coast and southern California, similar to the pattern in February. As the month progressed, zones of high pDA likelihood, or "hotspots," intensified and moved more offshore along the central coast near the Santa Barbara Channel, San Luis Obispo, Monterey Bay, around San Francisco Bay, and throughout much of the Southern California Bight to San Diego (mid to late March). HABMAP particulate domoic acid data are not yet available for March. Similar patterns were predicted for cellular DA (cDA) risk as those for pDA, although often with more intensity and further offshore, particularly in San Luis Obispo and Monterey Counties. Unlike in February, both pDA and cDA probabilities were high much of March in a narrow band along the North Coast, suggesting a return to seasonal domoic acid problems in that region. However, a razor clam health advisory is still in effect for Humboldt and Del Norte Counties due to domoic acid. The only California Sea Lion stranding from suspected DA toxicosis in March was reported by The Marine Mammal Center (TMMC) on March 10th in Monterey County, a region that was a potential hot spot according to C-HARM and HABMAP sampling; no other regions reported suspected DA toxicosis cases in March.

Alexandrium - CDPH did not observe any Alexandrium spp. at sites sampled in March, consistent with HABMAP sampling, and there are no recreational shellfish advisories related to PSP at this time.

*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

Four water samples were collected at Santa Cruz Wharf in March. Molecular probes for toxigenic Pseudo-nitzschia in the "seriata" class are conducted for this site, and was detected twice: once on March 3 (above the bloom threshold level) and on March 17 (below the threshold). Alexandrium spp. were not detected. 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

Five water samples were collected at Cal Poly Pier in March. Pseudo-nitzschia "delicatissima" was detected on three occasions (March 1, 22, 29) as was Pseudo-nitzschia "seriata" (March 1, 8, 29). All detections were below the bloom threshold value except for Pseudo-nitzschia "seriata" on March 1. Alexandrium spp. were detected once on March 22 (below the threshold). 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 March.

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

Santa Monica Pier

Four water samples were collected at Santa Monica Pier in March. Pseudo-nitzschia "delicatissima" was detected on each occasion (March 8, 15, 22, 29). All detections were below the bloom threshold value except on March 22. Pseudo-nitzschia "seriata" was also detected on each occasion, with March 22, 29 values being above the threshold. Alexandrium spp. were not detected 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 available for April 2020 through March 2021.

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