Pseudo-nitzschia and Domoic Acid Predictions - C-HARM tells us where conditions are suitable for Pseudo-nitzschia spp. (all size classes) to grow well and where they might be more likely to produce Domoic acid (DA). In July, suitable habitat for Pseudo-nitzschia spp. was spread throughout coastal California with slightly lower probabilities in the Southern California Bight and higher probabilities in offshore regions as the month progressed. C-HARM predicted high but patchy particulate DA (pDA) throughout most of the state, with very high probabilities of high DA along sections of the Humboldt and Sonoma coastlines, Monterey Bay, and the Southern California Bight (including the Santa Barbara Channel). Notably, nearshore probabilities of pDA were low for the San Luis Obispo coast but high in offshore eddy-like patches. C-HARM also indicates very high probabilities in cellular DA (cDA) distributed in patches along the Humboldt and Sonoma coastline and Monterey Bay, areas where Pseudo-nitzschia was also indicated to be most vigorous according to C-HARM. Patches of high cDA probability in the SB Channel and the Bight "blip" on and off over the course of July. In comparison with the HABMAP measurements where we have the July data already available, bloom levels of both P. seriata and delicatissima size classes were sustained at Newport Beach Pier throughout July. Blooms levels of P. delicatissima (the less toxigenic size class) were seen at Santa Monica Pier from mid-July onward. Data are not yet recorded for Stearns Wharf in Santa Barbara, but Cal Poly pier did see blooms levels of the P. seriata size class in mid-July. DA data were not yet available for any of the HABMAP sites. Animal strandings potentially related to DA were concentrated in central California throughout July, consistent with the high C-HARM pDA probabilities in this region but inconsistent with the very low abundances of Pseudo-nitzschia spp. and low DA recorded at the Santa Cruz Wharf. The central CA strandings were still slightly lower than the average stranding rate for July recorded since 1998 by The Marine Mammal Center located in Sausalito, CA. The two sea lion strandings in LA county and one in Orange County are consistent with the bloom levels of toxigenic species of Pseudo-nitzschia spp. recorded at pier sites in the region. CDPH recorded their highest abundances of Pseudo-nitzschia spp. along the North Coast (e.g., Humboldt Co., Sonoma Co., and the San Francisco Bay), as well as elevated abundances at Southern California Bight sites.
Alexandrium - HABMAP records for Alexandrium spp. at pier sites indicate no Alexandrium in July. CDPH recorded slightly elevated levels at central coast sites in San Luiso Obispo County and elevated saxitoxin in shellfish, prompting the safety notification for paralytic shellfish poisoning (PSP) in sport-harvested whole scallops and all clams to continue into mid-August. By the end of July, PSP safety notifications were lifted for Marin, Sonoma, and Santa Barbara Counties.
HABMAP Monitoring Sites
Note that data for some stations are not shown because they are not yet recorded in the public HABMAP archive.
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.
Water samples were collected at Santa Cruz Wharf five times in the month of July. Pseudo-nitzschia seriata group and domoic acid were not detected in any of the samples. Alexandrium were detected below bloom levels on all five sampling dates. Santa Cruz Wharf does not count for Pseudo-nitzschia delicatissima group.
Water samples were collected at Cal Poly Pier four times in the month of July. Pseudo-nitzschia delicatissima group was detected above bloom levels on July 14th and 21st. Pseudo-nitzschia seriata group and Alexandrium spp. were not detected in any of the samples. Domoic Acid results are not yet available for the month of June and July.
Water samples were collected at Santa Monica five times in the month of July. Pseudo-nitzschia delicatissima group was detected above bloom levels on July 22nd and 29th. Pseudo-nitzschia seriata group was detected below bloom levels on July 22nd and Alexandrium spp. were not detected in any of July water samples. Domoic Acid results are not yet available for the month of June and July.
Water samples were collected at Newport Beach Pier five times in the month of July. Pseudo-nitzschia delicatissima group and Pseudo-nitzschia seriata group were detected above bloom levels on July 15th, 22nd, and 29th. Alexandrium spp. were not detected in any of the samples. Domoic Acid results are not yet available for the month of July.
Scripps Pier Pseudo-nitzschia spp., Alexandrium spp., and domoic acid results are not yet available at this time.
From 1-31 July 2019, water samples were collected by volunteers and sent to the California Department of Public Health (CDPH) for analysis. Pseudo-nitzschia spp. were detected in 54 of the 122 samples. Pseudo-nitzschia spp. were recorded at Common density levels in five of the samples:
- July 3rd at Wilson Creek (20% composition)
- July 3rd at Hunter Rock (15% composition)
- July 4th at Trinidad Pier (10% composition)
- July 11th at Marina Bay Harbor (25% composition)
- July 12th at Trinidad Pier (15% composition)
Alexandrium spp. were detected in 16 of 63 samples in the month of July at low density levels. You can also view CDPH weekly map layers of Pseudo-nitzschia and Alexandrium here.
Data are provided by the California Department of Public Health, Environmental Management Branch.
CDPH and OEHHA Health Advisories
The California Department of Public Health (CDPH) lifted the shellfish advisory for sport-harvest whole scallops and all clams in Sonoma, Marin and Santa Barbara counties on July 23rd and San Luis Obispo County on August 13th. The annual mussel quarantine remains in effect through October 31st.
For the latest closures and updates, please visit the CDFW Health Advisories page as a central location of information related to CDPH and/or OEHHA health advisories.
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), the California Wildlife Center (CWC), the Marine Mammal Care Center Los Angeles (MMCC-LA), Marine Animal Rescue (MAR), the Pacific Marine Mammal Center (PMMC), and SeaWorld act like an emergency room by working to rescue and rehabilitate sick and injured marine mammals, seabirds, and sea turtles.
Among the six rehabilitation centers we have date for a total of 19 marine mammal strandings presented with symptoms of domoic acid toxicosis in the month of July with 6 in Monterey County.
SeaWorld and the Marine Mammal Care Center-Los Angeles did not record any strandings due to suspected DA in July.
July marine mammal strandings suspected due to DA toxicosis occurred in the following counties:
- Sonoma - 1 (TMMC)
- Alameda - 1 (TMMC)
- San Francisci Bay - 1 (TMMC)
- San Mateo - 3 (TMMC)
- Santa Cruz - 3 (TMMC)
- Monterey - 6 (TMMC)
- San Luis Obispo - 1 (TMMC)
- Los Angeles - 2 (CWC & MAR)
- Orange County - 1 (PMMC)
At this time we do not have data from the North Coast Marine Mammal Center or the Channel Islands Marine Wildlife Institute.