C-HARM
Model 

HABMAP

CDPH Phytoplankton Data 

TMMC
Strandings Data 

Pseudo-nitzschia - 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. In October, the probability of a Pseudo-nitzschia spp. bloom was still high all along the coast with low offshore probabilities in the Southern California Bight. Time series of the Harmful Algal Bloom Monitoring and Alert Program (HABMAP) data are plotted below for all of 2018 through October to give a seasonal perspective. For the month of October, these data show a peak in Pseudo-nitzschia abundance more in the latter half of the month at most sites, except the Santa Cruz Municipal Wharf where things were relatively quiescent. The increase at other stations reached "bloom" levels (~10,000 cells/L) and appears to have been a mixture of the larger ("seriata") and smaller ("delicatissima") size class of Pseudo-nitzschia. These size classes generally correspond to more toxigenic and non-toxigenic species, respectively. The highest CDPH measurements of Pseudo-nitzschia were along the Humboldt Coast, with moderate levels (<12% relative abundance) in the San Diego area and Santa Cruz Wharf, underscoring how variable these measurements can be.

Domoic Acid - C-HARM predicted the highest likelihood of particulate domoic acid (pDA) production in the Southern CA Bight, the offshore region of central CA, and to some extent in the nearshore zone of the North (Humboldt) Coast, consistent with high Pseudo-nitzschia counts from CDPH, although with lower probabilities than in the previous month of September. Note we do not make HABMAP measurements of DA north of Monterey Bay, and those that are available for October show low DA at the Santa Cruz Municipal Wharf, consistent with low nearshore C-HARM probabilities of pDA. Cellular domoic acid (cDA) predictions, which should tell us where Pseudo-nitzschia cells are likely to be most toxic on a per-cell basis, were still highest along the North Coast, although reduced along the Sonoma and central CA coastline relative to September. The latter is consistent with the September shellfish advisory in Humboldt County as well as the CDPH phytoplankton monitoring. Sea lion strandings from DA toxicosis recorded by The Marine Mammal Center in Sausalito went from one in September to five in October from San Luis Obispo to Santa Cruz, San Francisco, and Sonoma County. It is difficult to know in which offshore or nearshore environment the animals actually acquired the DA, but given that the offshore probabilities of DA from C-HARM are highest offshore along much of the coastline, that general region is a likely target.

Alexandrium - Much like the trend in the time series from the Harmful Algal Bloom Monitoring and Alert Program (HABMAP) data into September, Alexandrium spp. percent composition from CDPH showed minimal activity in October, and the HABMAP data were consistent with that. There have been no PSP alerts from CDPH or CDFW.

C-HARM Model

HABMAP Observations

Santa Cruz Municipal Wharf

Cal Poly Pier

Stearns Wharf

Santa Monica Pier

Newport Beach Pier

CDPH observations for Pseudo-nitzschia spp. and Alexandrium spp.

From 1-29 October 2018, water samples were collected by volunteers and sent to the California Department of Public Health (CDPH) for analysis. Pseudo-nitzschia spp. were detected in 29 of the 72 samples. Percent composition of Pseudo-nitzschia spp. was greatest on October 1st and 15th at Humboldt Bay (35% and 30% composition respectively) and October 6th at Trinidad Pier (35% composition). Alexandrium spp. were detected at low levels (<1%) in 5 of the 30 sites sampled. You can also view CDPH weekly map layers of Pseudo-nitzschia and Alexandrium here. On September 13th, CDPH released an advisory to not eat recreationally harvested shellfish in Humboldt County due to dangerous levels of domoic acid that can cause Amnesic Shellfish Poisoning (ASP).

Note the annual mussel quarantine is still in effect. The mussel quarantine is an annual event that happens due to dangerous levels of biotoxins that may be present in mussels gathered by the public anywhere on the California coast, including bays, inlets, and harbors. For the latest closures and updates, please visit the California Department of Fish and Wildlife (CDFW) Health Advisories page.

Data are provided by the California Department of Public Health, Environmental Management Branch.