SEPTEMBER HIGHLIGHTS

*note: for the full suite of HAB taxa sampled weekly, see the SCCOOS and CeNCOOS HABMAP database and the Imaging FlowCytobot Dashboard.

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). Three independent models are run daily to produce nowcasts and three-day forecasts of the probability of a bloom, the probability of a DA event for particulate DA only, and the probability of a DA event for the cellular portion of DA only. Here, in the bulletin, we summarize nowcasts for the month.
• C-HARM predictions for Pseudo-nitzschia spp. blooms in September intensified from August, indicating statewide potential for large blooms, sometimes extending very far offshore north of Pt. Conception. 
• HABMAP pier sampling painted a different picture with fairly quiescent Pseudo-nitzschia spp. activity in the nearshore environment, as has been the case for much of the summer. Pseudo-nitzschia spp. were rarely detected at all sites except Scripps Pier, where the less toxigenic size class, "delicatissima," did reach bloom levels on two occasions. This is interesting given the presence of a toxic Pseudo-nitzschia bloom in the central and southern California regions, as evidenced by a major marine mammal stranding and mortality event from DA toxicosis in mid-August to mid-September.
• Pseudo-nitzschia activity from CDPH coastal sampling, however, detected the more toxigenic size class, Pseudo-nitzschia 'seriata,' as 'Abundant' at several sites across central and northern California and "Common" at sites throughout the entire state. 
• The CA Imaging FlowCytobot Network images from the piers in September did not detect a Pseudo-nitzschia bloom, consistent with the weekly HABMAP sampling. Instead, most sites recorded significant dinoflagellate blooms, some that turned into "red tides" of bioluminescence from Lingulodinium polyedra (Santa Barbara to San Diego). As reported in the last bulletin, an IFCB onboard the late August CalCOFI cruise did image high densities of Pseudo-nitzschia in offshore waters of the Santa Barbara Channel, corroborating an offshore origin to the DA event and ensuing marine mammal stranding event.
• C-HARM probabilities for particulate domoic acid (pDA) at the beginning of September reflected patterns established at the end of August, where the Santa Barbara Channel was the epicenter of high DA risk, while a lot of DA potential developed in central CA and large swaths of the Southern California Bight. By mid-September, a large eddy of high probabilities off the coast of San Diego suggested high DA in that region, while areas surrounding Monterey Bay were also very high in risk potential.
• The pattern for C-HARM predictions of cellular domoic acid (cDA) probability diverged from that of pDA since there were no elevated probabilities in the Santa Barbara Channel region. Cellular toxicity was more likely to be elevated in a narrow coastal band from Pt. Conception to the Oregon border, with implications for the Dungeness crab season opener in northern California.
• Unfortunately, the results for DA from HABMAP sampling is still limited for September. Despite the large marine mammal stranding event in August and September, DA was not detected at any pier sampling site. This is, of course, consistent with the concurrent observations of low Pseudo-nitzschia abundance. Very high levels of domoic acid (90 micrograms/L) were measured, however, in the middle of the Santa Barbara Channel and well below the surface, as part of an ECOHAB project piggybacking on a Plumes and Blooms cruise towards the end of August. Surface DA was also elevated offshore according to measurements from the ECOHAB sampling and from SCCWRP/SCCOOS opportunistic sampling with the help of the Santa Barbara ChannelKeepers (funded by the NOAA HAB Event Response program).
• The DA event that began in mid- to late-August and extended well into September left over 400 animals stranded or recovered (many humanely euthanized at care centers). A tally of animals from central to southern California is provided below, however, note that we do not yet have a tally from CIMWI in Santa Barbara, which recovered the majority of animals affected by this event, many of which were adult females, with some notable exceptions, such as a Northern fur seal at CIMWI. C-HARM pDA predictions tracked the movement of stranded animals from mid- to late-August as the strandings began in Ventura, moved into the entire Santa Barbara Channel area and then moved to Orange County and a bit further south, as well as north to central CA where TMMC picked up many animals throughout September. Predictions of pDA extent matched stranding patterns well and indicated that this offshore bloom was only detectable by C-HARM since HABMAP (nor the IFCB network) did not detect the Pseudo-nitzschia bloom at pier sites. Offshore sampling, as discussed above, did yield high enough DA levels to explain the marine mammal impacts (at least for the Santa Barbara Channel, where sampling was focused).
• Note that CDPH lifted the razor clam domoic acid health advisory on June 27th, but the annual quarantine on consuming recreational mussels was still in effect until October 31st.

Alexandrium -

• CDPH detected Alexandrium spp. at background "Present" relative abundance levels at sampling sites throughout central and northern California in September despite the fact that a Paralytic Shellfish Poisoning (PSP) advisory was issued for San Mateo county in central/northern California on September 2. Those results are generally consistent with HABMAP sampling, which detected Alexandrium spp. at low levels at Santa Cruz Municipal Wharf, Cal Poly Pier, and Scripps Pier at least once in the month. 

Summary written by Clarissa Anderson on 2 November 2022

Pseudo-nitzschia "seriata" was detected at "Common" density levels on 5 occasions:

• 2022-09-01 10% Orick Beach
• 2022-09-08 33% Port San Luis, Diablo Cove
• 2022-09-13 33% Trinidad Pier
• 2022-09-19 30% Morro Bay, Boat Launch
• 2022-09-22 20% Port San Luis, Diablo Cove

Pseudo-nitzschia "seriata" was detected at "Present" density levels on 14 occasions: 

• 2022-09-01 1% Santa Monica Bay
• 2022-09-02 9% Bodega Harbor, USCG Dock
• 2022-09-06 1% La Jolla, Scripps Pier
• 2022-09-06 5% Humboldt Bay, Indian Is. Ch.
• 2022-09-07 4% Goleta Pier
• 2022-09-12 1% Kashia Coastal Reserve
• 2022-09-12 1% Humboldt Bay, Indian Is. Ch.
• 2022-09-12 2% Morro Bay, Boat Launch
• 2022-09-13 1% Port San Luis, Diablo Cove
• 2022-09-13 9% Hunter Rock, north
• 2022-09-15 4% Mendocino, Noyo Harbor
• 2022-09-19 2% Humboldt Bay, Indian Is. Ch.
• 2022-09-26 1% Humboldt Bay, Indian Is. Ch.
• 2022-09-27 5% Wilson Creek

Pseudo-nitzschia "seriata" was detected at "Rare" density levels on 22 occasions:

• 2022-09-02 0.5% Bolsa Chica
• 2022-09-03 0.5% Palos Verdes, OFFSHORE
• 2022-09-04 0.5% Point Dume, offshore
• 2022-09-05 0.5% Tomales Bay, Lease #M430-15
• 2022-09-06 0.5% Morro Bay, Boat Launch
• 2022-09-06 0.5% Mendocino, Noyo Harbor
• 2022-09-08 0.5% Morro Bay, North T-Pier
• 2022-09-10 0.5% San Simeon Pier
• 2022-09-12 0.5% Tomales Bay, Lease #M430-05
• 2022-09-13 0.5% Bodega Harbor, USCG Dock
• 2022-09-14 0.5% Monterey, Stillwater Cove
• 2022-09-16 0.5% San Simeon Pier
• 2022-09-18 0.5% Pacifica Pier
• 2022-09-19 0.5% Tomales Bay, Lease #M430-15
• 2022-09-19 0.5% Catalina Island, Avalon Bay
• 2022-09-22 0.5% Santa Cruz Is., Prisoners Hrbr
• 2022-09-22 0.5% Monterey, Stillwater Cove
• 2022-09-22 0.5% GFNMS, San Francisco Line 6E
• 2022-09-24 0.5% Marin, OFFSHORE
• 2022-09-26 0.5% Tomales Bay, Lease #M430-15
• 2022-09-26 0.5% Mendocino, Noyo Harbor
• 2022-09-30 0.5% Bolsa Chica

Alexandrium spp. were detected in 29 of the 100 samples: 

Alexandrium spp. were not detected at "Common" density levels. 

Alexandrium spp. were detected at "Present" density levels on 12 occasions: 

• 2022-09-08 1% Port San Luis, Diablo Cove
• 2022-09-11 1% Pacifica Pier
• 2022-09-12 3% Morro Bay, Boat Launch
• 2022-09-12 5% Tomales Bay, Lease #M430-05
• 2022-09-13 2% Bodega Harbor, USCG Dock
• 2022-09-13 5% Port San Luis, Diablo Cove
• 2022-09-19 1% Mendocino, Noyo Harbor
• 2022-09-21 1% Santa Cruz, Capitola Pier
• 2022-09-22 4% Port San Luis, Diablo Cove
• 2022-09-26 5% Mendocino, Noyo Harbor
• 2022-09-26 8.5% Tomales Bay, Lease #M430-14
• 2022-09-28 2% Marin, OFFSHORE

Alexandrium spp. were detected at "Rare" density levels on 17 occasions: 

• 2022-09-02 0.5% San Francisco, Presidio Pier
• 2022-09-04 0.5% Point Dume, offshore
• 2022-09-05 0.5% Tomales Bay, Lease #M430-15
• 2022-09-06 0.5% Morro Bay, Boat Launch
• 2022-09-06 0.5% La Jolla, Scripps Pier
• 2022-09-07 0.5% Santa Cruz Wharf
• 2022-09-08 0.5% Morro Bay, North T-Pier
• 2022-09-12 0.5% La Jolla, Scripps Pier
• 2022-09-14 0.5% Santa Cruz, Capitola Pier
• 2022-09-19 0.5% Catalina Island, OFFSHORE
• 2022-09-19 0.5% Tomales Bay, Lease #M430-15
• 2022-09-19 0.5% Morro Bay, Boat Launch
• 2022-09-21 0.5% Bean Hollow State Beach
• 2022-09-22 0.5% Monterey, Stillwater Cove
• 2022-09-22 0.5% GFNMS, San Francisco Line 6E
• 2022-09-24 0.5% GFNMS, Marin Line 4E
• 2022-09-24 0.5% Marin, OFFSHORE