Pseudo-nitzschia and Domoic Acid Predictions - 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 domoic acid (DA). In September, suitable habitat for Pseudo-nitzschia spp. was  spread throughout coastal California, as it was in August, although with variable degrees of growth potential evidenced by the model for the Southern California Bight and for the Sonoma Coast throughout the month. This suggests a more patchy abundance of cells in those regions. C-HARM predicted high probability of particulate DA (pDA) but very patchy particulate DA (pDA) throughout most of the state, with the greatest probabilities of high DA along sections of the Sonoma coastline, Half Moon Bay, Monterey Bay, and the Southern California Bight (including the Santa Barbara Channel and the transition region around Pt Conception). As in August, nearshore probabilities of pDA were low for the San Luis Obispo coast but high in offshore eddy-like patches. The notable difference from August was the decreasing likelihood of high pDA along the North Coast/Humboldt Coast region.  C-HARM indicates very high probabilities in cellular DA (cDA) distributed in patches. These patches wax and wane over the course of the month but are persistently high along the Sonoma coastline and Marin County, Half Moon Bay, just south of Monterey Bay. Patches of high cDA probability around Pt. Conception and San Miguel Island appeared on and off in the SB Channel proper.

In comparison with the Harmful Algal Bloom Monitoring Alert Program (HABMAP) measurements where we have the September data already available, bloom levels of the P. "delicatissima" size class occurred at various times throughout the month in the Southern California Bight at Newport Beach Pier (Orange Co.) and Scripps Pier (San Diego Co.), Stearns Wharf in Santa Barbara, but not at the Santa Monica Pier. The P. "seriata" (i.e., more toxigenic) size class never reached bloom levels but showed an uptick in abundance at several southern sites, while P. delicatissima size class rose slightly at Cal Poly Pier (San Luis Obispo Co.) in late Sept. A similar uptick in P. seriata size class was seen at the Santa Cruz Wharf in September but below bloom levels. Of the HABMAP sites, DA data were only available for Santa Cruz Wharf where none was detected throughout the month of September, consistent with the low cDA predicted by C-HARM for the Monterey Bay area but inconsistent with the high pDA predicted for the area. Animal strandings potentially related to DA were concentrated in central California throughout September, consistent with the high cDA and pDA event probabilities predicted by C-HARM in this region but inconsistent with the low abundances of Pseudo-nitzschia spp. recorded at the Santa Cruz Wharf.

CDPH recorded their highest relative abundances of Pseudo-nitzschia seriata in Humboldt Bay area, the San Mateo Coast (Ano Nuevo Beach), and Sonoma Coast (Bodega Harbor) regions, as well as San Luis Obispo Co. where HABMAP recorded a slight rise in the non-toxigenic size class of Pseudo-nitzschia. As in August, Pseudo-nitzschia was not observed as a large proportion of the phytoplankton community in the Southern California Bight, although this is inconsistent with the high abundance values of the mostly non-toxigenic size class observed at Newport Beach Pier (Orange Co.) and Scripps Pier (San Diego Co.), and Stearns Wharf in Santa Barbara via the HABMAP pier sampling program, highlighting the patchy nature of phytoplankton species composition from day to day and site to site, as well as the difficulty associated with bulk Pseudo-nitzschia measurements that don't discriminate species. CDPH issued an Amnesic Shellfish Poisoning (ASP) warning from domoic acid on October 15th for Humboldt and Mendocino Counties.

Alexandrium - HABMAP records for Alexandrium spp. at pier sites. As in August, Cal Poly Pier (SLO Co.) was the only site showing a slight rise in Alexandrium spp. abundance in August. CDPH sampling, on the other hand, showed very slightly elevated relative abundance outside San Francisco Bay and near Bodega Bay. Lab results for of paralytic shellfish (PSP) toxins in shellfish led to an early September alert from CDPH on the risk of PSP toxins in mussels, clams, and whole scallops from Sonoma Co.

Santa Cruz Wharf

Water samples were collected at Santa Cruz Wharf four times in the month of September. Pseudo-nitzschia seriata group and Alexandrium were detected below bloom levels. Domoic Acid was not detected in any of the samples. Santa Cruz Wharf does not count for Pseudo-nitzschia delicatissima group since they use genetic probes for P. australis and P. multiseries (both seriata group). 

Monterey Wharf

Water samples were collected at Monterey Wharf two times in the month of September. Pseudo-nitzschia seriata group and Alexandrium spp. were not detected in any of the samples. Domoic Acid results are not yet available for Monterey Wharf.

Cal Poly Pier

Water samples were collected at Cal Poly Pier four times in the month of September. Pseudo-nitzschia delicatissima group was detected below bloom levels on September 15th and 22nd. Domoic Acid results are not yet available for the months of July, August and September.  

Stearns Wharf

Water samples were collected at Stearns Wharf five times in the month of September. Pseudo-nitzschia delicatissima group was detected above bloom levels on September 23rd and 30th. Pseudo-nitzschia seriata group was detected below bloom levels and Alexandrium spp. were not detected in any of the samples. Domoic Acid results are not yet available for Stearns Wharf.

Santa Monica Pier

Water samples were collected at Santa Monica five times in the month of September. Pseudo-nitzschia delicatissima group was detected below bloom levels and Pseudo-nitzschia seriata group and Alexandrium spp. were not detected in any of the samples. Domoic Acid results are not yet available.  

Scripps Pier

Water samples were collected at Scripps Pier four times in the month of September but results are only available for September 3rd where Pseudo-nitzschia deli and seriata were detected below bloom levels and Alexandrium spp. were not detected. Particulate domoic acid results are not yet available for Scripps Pier for June - September. 

At this time we do not have data from the North Coast Marine Mammal Center or the Channel Islands Marine Wildlife Institute.  

California Sea Bird Strandings from Suspected DA Toxicosis

Data coming soon from Wildlife Rehabilitation Medical Database (WRMD) and BeachCOMBERS.