October 2024

Summary written by Dr. Clarissa Anderson, 23 December 2024

– HAB Bulletin v2 –

The team welcomes any and all feedback on this new format of the California Harmful Algal Bloom bulletin, and extend our gratitude for your continued patience as we work through delays in development & data availability.

SUMMARY: At the beginning of October, over ten Ca Sea Lion stranding cases in central California and fewer peppered throughout southern California seemed to be spillover from the September domoic acid (DA) resurgence. There is a slight indication of mid-month bloom conditions at some nearshore sites and scattered high-DA conditions in northern California where the Dungeness crab fishery opening was delayed in November due, in part, to high levels of DA.
The C-HARM predictions for particulate domoic acid (DA) showed scattered offshore patches of high probability across much of California early in October. By mid October, coastal central California was predicted to have very high pDA event risk, and this waned by the end of October, with high probabilities hugging some very nearshore coastal zones statewide. Predictions of the cellular fraction of DA suggested highest risk confined to patches along the coast form Pt. Conception to the Oregon border earlier in the month of October, weakening to medium risk by the end of the month, somewhat consistent with Dungeness crab fishery delays in November associated with DA risk. Bloom levels of Pseudo-nitzschia cells were predicted to be highest from mid to end of October along the central coast but with no concomitant DA measurements or associated impacts in that region.
The view from CalHABMAP dada at the piers showed bloom levels of the smaller, less toxigenic “delicatissima” size class of Pseudo-nitzschia at Newport Beach Pier and the larger, more toxigenic size class “seriata” (along with relatively high DA levels) at Stearns Wharf, Santa Barbara in late September. Bloom levels of the “delicatissima” size class were just met at Newport Beach Pier and almost met at Scripps Pier in San Diego in mid October. The “seriata” size class approached bloom levels at Newport Beach Pier and Stearns Wharf (with low DA concentrations) in mid-October. The only other site where Pseudo-nitzschia cells were observed in October was Bodega Marine Laboratory, with non-bloom levels in mid-late October. No DA was detected at any HABMAP site except Stearns Wharf in October.
Time series of automatic images from robotic microscopes (IFCBs) classified to the genus level did not capture Pseudo-nitzschia activity at Santa Cruz Wharf — mostly the dinoflagellates, Akashiwo and Prorocentrum. The same was true for Scripps Pier – mostly the dinoflagellates, Prorocentrum and Lingulodinium polyedra – and no Pseudo-nitzschia, which is inconsistent with HABMAP manual sampling, which picked up moderate abundances of P. “deli” class cells at Scripps Pier in October. Indeed, the time series of the Pseudo-nitzschia spp. class at Stearns Wharf from the machine learning model shows non-detectable levels for the entire month of October, counter to HABMAP sampling at that site. As reported in the last bulletin, this is an active area of research for our team to better understand the discrepancy.
The state of California’s phytoplankton sampling results are somewhat consistent with the HABMAP pier observations. Relative abundance of Pseudo-nitzschia “seriata” was recorded as “Common” at San Luis Obispo and Santa Barbara sites in early October and then as “Abundant” in Santa Barbara in late October, consistent with cell counts approaching bloom levels at the HABMAP Stearns Wharf location. Only low levels were observed at San Diego sites, unlike the HABMAP results. “Common” levels were noted at the northern Del Norte site in mid-October, which is relevant considering the subsequent CDPH advisory on Nov. 1 to not eat sport-harvested Dungeness Crab from the Oregon border to Reading Rock State Marine Reserve as well as the delay in the commercial Dungeness crab fishery opening in northern California in early November. The advisory was later expanded to Pt Reyes. CDPH advisories for domoic acid risk in bivalves in Santa Barbara County were issued in response to the DA event in September but were lifted on October 23rd just before the annual recreational mussel quarantine was lifted on October 30th.
Marine mammal strandings from suspected DA toxicosis/intoxication continued to be higher than background levels into early October after the local peak in September and following a much larger event in August. Most of the animals were collected by The Marine Mammal Center of Sausalito and thus had a central California stranding origin. The rest of the recorded cases were from Santa Barbara and southern California centers. No animals were reported as stranded with symptoms of DA poisoning at the end of October, which suggests that the bloom levels observed at the coast in southern California were perhaps confined to the nearshore zone and/or were too ephemeral or nontoxic to lead to impacts in marine mammal populations (as predicted by the C-HARM model at the end of the month).
Alexandrium spp. were active in October according to the HABMAP pier sampling, with elevated levels recorded at Santa Cruz Wharf (early Oct) and Bodega Marine Laboratory (mid-end Oct). This is in stark contrast to CDPH phytoplankton monitoring results that indicate Alexandrium spp. were either Rare or Absent at all California sites sampled. The Paralytic Shellfish Poisoning (PSP) advisory for sport-harvested shellfish from Sonoma and Humboldt Counties was lifted on October 8th but not in Marin and Monterey Counties until Nov. 12th.

Particulate Domoic Acid

Particulate domoic acid (pDA) is the measurement of total domoic acid toxin that is potentially extant in a given area. This forecast provides a probability for where that concentration of toxin is predicted to exceed the threshold that classifies a Harmful Algal Bloom (> 500 nanograms per liter).

The C-HARM v3 model generates nowcast and forecasts of the probability of Pseudo-nitzschia concentrations of in excess of 10,000 cells/L, the probability of particulate domoic acid > 500 nanograms/L, and the probability of cellular domoic acid > 10 picograms/cell in California and Southern Oregon coastal waters. Inputs for the model include near real-time satellite observations, gap-filled chlorophyll a, 486nm reflectance, and 551nm reflectance fields from the S-NPP NOAA VIIRS sensor plus nowcast and forecast data of surface salinity, sea surface temperature, and surface currents from WCOFS ROMS.

Cellular Domoic Acid

Cellular domoic acid (cDA) is the measure of total domoic acid toxin calculated per cell of Pseudo-nitzschia. This forecast provides a probability for where those cells are expected to be producing toxin at high levels (> 10 picograms per cell).

The C-HARM v3 model generates nowcast and forecasts of the probability of Pseudo-nitzschia concentrations of in excess of 10,000 cells/L, the probability of particulate domoic acid > 500 nanograms/L, and the probability of cellular domoic acid > 10 picograms/cell in California and Southern Oregon coastal waters. Inputs for the model include near real-time satellite observations, gap-filled chlorophyll a, 486nm reflectance, and 551nm reflectance fields from the S-NPP NOAA VIIRS sensor plus nowcast and forecast data of surface salinity, sea surface temperature, and surface currents from WCOFS ROMS.

Pseudo-nitzschia

Pseudo-nitzschia is a neurotoxin producing diatom that is observed along the California Coast. Blooms of this phytoplankton can be detrimental to surrounding marine ecosystems. This forecast provides a probability for where the concentration of cells in the water exceed the threshold of a Harmful Algal Bloom ( > 10,000 cells/L).

The C-HARM v3 model generates nowcast and forecasts of the probability of Pseudo-nitzschia concentrations of in excess of 10,000 cells/L, the probability of particulate domoic acid > 500 nanograms/L, and the probability of cellular domoic acid > 10 picograms/cell in California and Southern Oregon coastal waters. Inputs for the model include near real-time satellite observations, gap-filled chlorophyll a, 486nm reflectance, and 551nm reflectance fields from the S-NPP NOAA VIIRS sensor plus nowcast and forecast data of surface salinity, sea surface temperature, and surface currents from WCOFS ROMS.

California Harmful Algal Bloom Monitoring & Alert Program

Differentiating Pseudo-nitzschia species by light microscopy is difficult. For this reason, Pseudo-nitzschia “seriata” does not refer to an actual species but rather the larger size class of Pseudo-nitzschia, which is generally a more toxigenic group of species. Alternatively, Pseudo-nitzschia “delicatissima” refers to the smaller size class that is generally non-toxigenic. The dashed line on the plots demarcates the 10,000 cells/L “bloom” threshold designated here for Pseudo-nitzschia populations only.

Data for some stations are not shown as they are not yet recorded in the public HABMAP archive.

These time series focus on data collected through the scope of this bulletin and the 12 month period that precedes it. Explore the variables and regions that make up the CalHABMAP collective dataset using the plot controls.

More information and data visualizations on the statewide HAB network and forecasting system is found on the California HABMAP website and on the SCCOOS Harmful Algal Bloom page.

A network of Imaging FlowCytobots (IFCBs) continuously photographs particles, such as plankton, in the water. Using machine learning, plankton species can be automatically identified. This will help improve the ability to detect and respond to Harmful Algal Blooms, including the ability to assess conditions that may lead to toxin production or blooms of toxin-producing algae.

These data, coupled with the image classification algorithms developed in collaboration with SCCOOS and CeNCOOS, allow for estimates of species composition over time. The time series below depict sampling outcomes across several California sites. Support provided by NOAA IOOS and CA OPC.

Additional images and data are available on the IFCB dashboard. NOTE: Eight shore station and offshore mooring sites are equipped with IFCBs, and five were generating data in September.]

Each month, water samples are collected by volunteers and sent to the California Department of Public Health (CDPH) for analysis.

The relative abundance of DA-producing Pseudo-nitzschia ‘seriata’ size class (left) and PSP toxin-producing Alexandrium spp. (right) are catalogued from sample locations (middle) within each county.

October 8

Humboldt County
____

CDPH lifts their consumption warning of sport-harvested bivalve shellfish in Humboldt County.

October 23

Santa Barbara County
____

CDPH lifts their consumption warning of sport-harvested bivalve shellfish in Santa Cruz & Santa Barbara County.

October 30

Del Norte, Marin, Monterey County
____

Statewide annual quarantine on mussels ends for all coastal counties except Del Norte, Marin & Monterey.

Water Sample Detailed Data

Date_Sampled	County	Sample_Site	PN_Percent_Comp	PN_Density	AL_Percent_Comp	AL_Density
2024-10-08	Del Norte	Wilson Creek	0.5	RARE	0	ABSENT
2024-10-08	Orange	Newport Bay, Back Bay	0	ABSENT	0	ABSENT
2024-10-09	Santa Cruz	Santa Cruz Wharf	0	ABSENT	0	ABSENT
2024-10-09	San Diego	Imperial Beach Pier	0	ABSENT	0	ABSENT
2024-10-10	San Diego	San Diego Bay, U.S. Navy Pier	0	ABSENT	0	ABSENT
2024-10-11	Santa Barbara	Santa Barbara Ch., Naples Pt	15	COMMON	0	ABSENT
2024-10-11	San Luis Obispo	Port San Luis, Diablo Cove	10	COMMON	0	ABSENT
2024-10-11	Orange	Bolsa Chica	0	ABSENT	0	ABSENT
2024-10-11	Los Angeles	Palos Verdes Rocky Pt Offshore	0	ABSENT	0	ABSENT
2024-10-12	San Diego	Pacific Beach Pier	0.5	RARE	0	ABSENT
2024-10-13	Los Angeles	Catalina Island, Avalon Bay	0	ABSENT	0	ABSENT
2024-10-14	San Diego	La Jolla, Scripps Pier	1	PRESENT	0	ABSENT
2024-10-14	Mendocino	Point Arena Pier	0.5	RARE	0	ABSENT
2024-10-14	Marin	Tomales Bay, Lease #M430-15	0	ABSENT	0	ABSENT
2024-10-14	San Luis Obispo	Morro Bay, Boat Launch	0	ABSENT	0	ABSENT
2024-10-15	Mendocino	Mendocino, Noyo Harbor	1	PRESENT	0	ABSENT
2024-10-15	Ventura	Ventura, Port Hueneme Pier	0	ABSENT	0	ABSENT
2024-10-15	Orange	Newport Bay, Back Bay	0	ABSENT	0	ABSENT
2024-10-16	Del Norte	Hunter Rock, north	10	COMMON	0.5	RARE
2024-10-16	Del Norte	Hidden Beach	4	PRESENT	0	ABSENT
2024-10-16	Santa Barbara	Goleta Pier	3	PRESENT	0	ABSENT
2024-10-16	Humboldt	Humboldt Bay, Indian Is. Ch.	0.5	RARE	0	ABSENT
2024-10-16	Sonoma	Bodega Harbor, USCG Dock	0	ABSENT	0	ABSENT
2024-10-16	San Mateo	Bean Hollow State Beach	0	ABSENT	0	ABSENT
2024-10-16	San Mateo	Pillar Point Harbor	0	ABSENT	0	ABSENT
2024-10-16	Santa Cruz	Santa Cruz Wharf	0	ABSENT	0.5	RARE
2024-10-16	Los Angeles	Manhattan Beach Pier	0	ABSENT	0	ABSENT
2024-10-16	Los Angeles	Santa Monica Pier	0	ABSENT	0	ABSENT
2024-10-16	Sonoma	Kashia Coastal Reserve	0	ABSENT	0	ABSENT
2024-10-17	Mendocino	Mendocino, Noyo Harbor	2	PRESENT	0.5	RARE
2024-10-17	San Luis Obispo	Pismo Pier	0	ABSENT	0	ABSENT
2024-10-18	Orange	Bolsa Chica	0	ABSENT	0	ABSENT
2024-10-18	Orange	San Clemente Pier	0	ABSENT	0	ABSENT
2024-10-19	San Mateo	Pillar Point Harbor	0.5	RARE	0	ABSENT
2024-10-19	Humboldt	Trinidad Pier	0.5	RARE	0	ABSENT
2024-10-21	San Luis Obispo	Morro Bay, Boat Launch	5	PRESENT	0.5	RARE
2024-10-21	San Diego	La Jolla, Scripps Pier	2	PRESENT	0	ABSENT
2024-10-21	Marin	Tomales Bay, Lease #M430-15	0.5	RARE	0.5	RARE
2024-10-21	Humboldt	Humboldt Bay, Indian Is. Ch.	0.5	RARE	0.5	RARE
2024-10-22	Santa Barbara	Santa Cruz Is., Prisoners Hrbr	61	ABUNDANT	0	ABSENT
2024-10-23	Del Norte	Wilson Creek	0.5	RARE	0	ABSENT
2024-10-23	Santa Cruz	Santa Cruz Wharf	0	ABSENT	0	ABSENT
2024-10-24	San Francisco	Oakland, Jack London Aquatic	0	ABSENT	0	ABSENT
2024-10-24	Marin	Point Richmond, Ferry Point	0	ABSENT	0	ABSENT
2024-10-25	Orange	Bolsa Chica	0	ABSENT	0	ABSENT
2024-10-27	San Luis Obispo	Cayucos Pier	3	PRESENT	0.5	RARE
2024-10-28	San Diego	La Jolla, Scripps Pier	1	PRESENT	0	ABSENT
2024-10-28	Humboldt	Humboldt Bay, Indian Is. Ch.	0.5	RARE	0	ABSENT
2024-10-28	Marin	Tomales Bay, Lease #M430-15	0	ABSENT	0	ABSENT
2024-10-29	San Luis Obispo	Morro Bay, Boat Launch	1	PRESENT	0	ABSENT
2024-10-29	Del Norte	Wilson Creek	0.5	RARE	0	ABSENT
2024-10-29	Marin	Drakes Bay, Chimney Rock LBS	0	ABSENT	0	ABSENT
2024-10-30	Marin	Richmond, Marina Bay Harbor	0	ABSENT	0	ABSENT
2024-10-30	Santa Cruz	Santa Cruz Wharf	0	ABSENT	0	ABSENT
2024-10-30	Santa Barbara	Goleta Pier	0	ABSENT	0	ABSENT
2024-10-30	San Mateo	Bean Hollow State Beach	0	ABSENT	0	ABSENT
2024-10-30	San Mateo	Pillar Point Harbor	0	ABSENT	0	ABSENT

Percent composition categories help us look at phytoplankton trends across an entire region to evaluate risk of biotoxin presence. Many other factors contribute to our evaluation of risk in an area. These samples are posted for informational purposes only. They are not intended to inform the public of the presence or lack of risk. For the latest health advisory information, see the CDPH Health Advisory Map below.

Suspect DA Strandings in Early October

Domoic acid (DA) is a potent neurotoxin produced by some diatom species of the genus Pseudo-nitzschia. Species exposed to DA can result in seizures, epilepsy, cardiomyopathy, and death depending upon the ingested dose. DA toxicosis commonly occurs in California sea lions (Zalophus californianus), presumably due to a combination of foraging behavior and seasonal movements.

The Marine Mammal Center (TMMC), Channel Islands Marine Wildlife Institute (CIMWI), California Wildlife Center (CWC), Marine Mammal Care Center Los Angeles (MMCC-LA), Pacific Marine Mammal Center (PMMC), SeaWorld, and Southwest Fisheries Science Center (SWFSC) act like an emergency room by working to rescue and rehabilitate sick and injured marine mammals, seabirds, and sea turtles.

California's Marine Mammal Stranding Network Map

This public acknowledgment serves to honor and respect Indigenous peoples and their land on which our organization resides. UC San Diego was built upon the territory of the Kumeyaay Nation. From time immemorial, the Kumeyaay people have been a part of this land, coast, and sea. Today, the Kumeyaay people continue to maintain their political sovereignty and cultural traditions as vital members of the San Diego community.
The nature and extent of observation that the Southern California Coastal Ocean Observing System directly supports is entirely within the historic purview of many distinct Indigenous nations & cultures, who subsisted on and shaped these coasts. With deep admiration & acknowledgement to these Indigenous peoples past and present, we hope to contribute our services to the shared vision of coastal stewardship and connection which they have created.