DECEMBER 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 -

•  * Important update to C-HARM in this bulletin. C-HARM version 3 is now operational at NOAA CoastWatch. Major change include: new operational circulation model (WCOFS) for currents, salinity, and temperature and VIIRS ocean color products in place of MODIS Aqua. WCOFS is a 4DVAR data assimilative model run at NOAA Coast Survey Development Lab (CSDL). Issues with salinity accuracy persist and have notable consequences for the Particulate Domoic Acid predictions, which we will address in these bulletins.   
• 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 December contain some pixelation from VIIRS. Early and mid-month are the most intense periods for possible Pseudo-nitzschia bloom development. As in prior months, this indicates vast statewide potential for large blooms sometimes extending very far offshore. This suggests a large percentage of false positives but also corroborates something we've seen for a while in the California Current, which is that conditions are fairly regularly conducive in most coastal zones to supporting Pseudo-nitzschia populations.  
• HABMAP weekly pier sampling indicated moderate to low Pseudo-nitzschia spp. activity in the nearshore environment, in keeping with recent trends at the piers. However, bloom levels were reached at several locations in December: Cal Poly Pier in late December and Santa Monica Pier in mid and late December, the latter being the more toxigenic size class, P. "seriata."
• Pseudo-nitzschia activity from CDPH coastal sampling in November, however, detected the more toxigenic size class, Pseudo-nitzschia 'seriata,' as 'Common', but not 'Abundant,' at a northern California site in Humboldt Bay and 'Present' at many sties throughout California.  
• A selection of CA Imaging FlowCytobot Network images from the piers and offshore buoys in mid-December illustrates some interesting latitudinal gradients from north to south. Imagery from Santa Cruz Wharf and further offshore at the MBARI Power Buoy in Monterey suggests there was bay-wide potential for an Akashiwo sanguinea bloom, which can be harmful to birds. There was some potential for a Lingulodinium polyedra bloom at Newport Beach Pier in Orange County but not so much further south a the offshore Del Mar mooring and Scripps Pier in San Diego. 
• C-HARM probabilities for particulate domoic acid (pDA) in the early part of December indicate that the greatest risk for DA exposure is the Southern California Bight and central coast from Point Conception to San Francisco Bay. Later in the month, this risk shifts south, with high probabilities from Point Conception into the Santa Barbara Channel and further south into the Bight.
• The pattern for C-HARM predictions of cellular domoic acid (cDA) probability shows patches of high risk from the north coast to southern California throughout the month with the most prolonged risk for high cDA along the Central Coast and along the South Coast mid to late December. A strong offshore bolus of potentially high cDA water forms late in the month off the central coast from Point Conception to San Francisco Bay. 
• Consistent with the high DA risk predicted by C-HARM for the central coast, there were two stranding cases from DA toxicosis in Santa Cruz, joining the four reported last month by TMMC from Santa Cruz and San Luis Obispo Counties in early December. Interestingly, IFCB images from the MBARI Power Buoy offshore in Monterey Bay show dinoflagellates becoming dominant around November 19 and the last diatom bloom with Pseudo-nitzschia populations prior to that, suggesting that if the California Sea Lions acquired DA from a bloom in the bay, it would have been many weeks prior to the strandings, or the animals ingested DA subsurface or in another coastal zone. The Santa Cruz Wharf IFCB did not capture any transient or short-lived Pseudo-nitzschia blooms in mid November to December either, mostly dinoflagellate-dominated communities. 
• CDPH lifted an advisory on January 9 for mussels, scallops, and most types of clams in Humboldt County due to PSP and ASP. However, the advisory related to sport-harvested razor clams from Humboldt and Del Norte counties remains in effect due to ASP risk. Given the low depuration (detox) rates of razor clams, DA levels in razor clams are usually more a reflection of long-term exposure to DA rather than real-time or recent bloom conditions. However, since this same advisory was lifted in June and then reinstated in November of this year, there has likely been persistent, if low-level, production of DA in the North Coast region. Note that the annual quarantine on consuming recreational mussels was lifted at the end of October, except for Humboldt, San Mateo, Monterey, and San Luis Obispo.

Alexandrium -

• CDPH did not detect any significant levels of Alexandrium spp. in December, which is a reduction in Alexandrium activity from November. In line with that, the Paralytic Shellfish Poisoning (PSP) advisory was lifted on January 9 for mussels, scallops, and most types of clams in Humboldt County. HABMAP detected only low levels of Alexandrium at several sites in December. 

Summary written by Clarissa Anderson on 24 January 2023

Pseudo-nitzschia "seriata" was detected at "Common" density levels once:

• 2022-12-05 10% Humboldt Bay, Indian Is. Ch.

Pseudo-nitzschia "seriata" was detected at "Present" density levels on 9 occasions: 

• 2022-12-02 5% Pillar Point Harbor
• 2022-12-06 4% Redondo Beach Pier
• 2022-12-07 1% Drakes Bay, Chimney Rock LBS
• 2022-12-09 1% Bolsa Chica
• 2022-12-12 2% La Jolla, Scripps Pier
• 2022-12-20 1% Goleta Pier
• 2022-12-23 3% Santa Monica Pier
• 2022-12-28 5% Santa Monica Pier
• 2022-12-30 2% Imperial Beach Pier

Pseudo-nitzschia "seriata" was detected at "Rare" density levels on 18 occasions:

• 2022-12-01 0.5% Imperial Beach Pier
• 2022-12-02 0.5% Bolsa Chica
• 2022-12-03 0.5% Palos Verdes Rocky Pt Offshore
• 2022-12-03 0.5% Catalina Island, Avalon Bay
• 2022-12-05 0.5% Tomales Bay, Lease #M430-15
• 2022-12-05 0.5% Wilson Creek
• 2022-12-06 0.5% Pillar Point Harbor
• 2022-12-07 0.5% Goleta Pier
• 2022-12-08 0.5% Imperial Beach Pier
• 2022-12-08 0.5% Hermosa Beach Pier
• 2022-12-12 0.5% Tomales Bay, Lease #M430-15
• 2022-12-14 0.5% Goleta Pier
• 2022-12-15 0.5% Port San Luis, Diablo Cove
• 2022-12-16 0.5% Palos Verdes Rocky Pt Offshore
• 2022-12-21 0.5% Lake Merritt Boating Center
• 2022-12-22 0.5% Imperial Beach Pier
• 2022-12-23 0.5% Bolsa Chica
• 2022-12-26 0.5% Tomales Bay, Lease #M430-15

Alexandrium spp. were detected in 6 of the 70 samples: 

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

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

Alexandrium spp. were detected at "Rare" density levels on 6 occasions: 

• 2022-12-01 0.5% Imperial Beach Pier
• 2022-12-07 0.5% Santa Cruz Wharf
• 2022-12-07 0.5% Goleta Pier
• 2022-12-15 0.5% Port San Luis, Diablo Cove
• 2022-12-21 0.5% Kashia Coastal Reserve
• 2022-12-29 0.5% Goleta Pier