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). C-HARM also tells us where DA might be more likely to occur at high levels. For May, we show the shift from the beginning of the month to the end, as multiple foci of high DA activity started to emerge in central CA and in southern CA, especially in the Los Angeles and Orange County areas. C-HARM appears to capture this expansion of not only Pseudo-nitzschia growth potential but also DA production as the probabilities of both Pseudo-nitzschia abundance and particulate DA increased in those focal regions over the course of the month. HABMAP observations of Pseudo-nitzschia spp. abundance indicate bloom conditions from southern Monterey Bay to Newport Beach Pier (no observations posted currently for Scripps Pier). One feature of this rise is that the proportion of "seriata" (toxigenic) relative to "delicatissima" (non-toxigenic) size-classes increases as we move south. This is consistent with the cluster of suspected DA-related animal strandings in the Los Angeles and Orange County areas at the end of May. However, strandings were also noted in central CA and in the San Diego area. Interestingly though, for the sites where DA samples have already been processed, there is no spike in DA observed at Newport Beach Pier in Orange County during May. Elevated DA is only seen at Santa Monica Pier. CDPH volunteer sampling in May captured the greatest increases in Pseudo-nitzschia percent composition at Santa Cruz, Santa Barbara Channel, Los Angeles, and San Diego sites. Observational discrepancies are expected given the extreme heterogeneity in phytoplankton composition patterns and toxin production across nearshore sites, which also vary with respect to the offshore environment.

Alexandrium - HABMAP records for Alexandrium at pier sites show the unexpected and perhaps unprecedented record for Santa Cruz Wharf in May 2019, when Alexandrium spp. abundance shot to 25,000 cells/L in early May. This alerted CDPH to sample more mussels to analyze for PSP. The mussels collected had PSP levels greater than 80 µg/100g, which resulted in the CDPH issuing a health advisory on May 10th to not eat sport-harvested mussels, clams or scallops in Santa Cruz County due to PSP toxins. CDPH later recorded a similar spike outside San Francisco Bay.

Santa Cruz Wharf

Water samples were collected five times at Santa Cruz Municipal Wharf in the month of May. Pseudo-nitzschia seriata group was detected below bloom levels and Alexandrium spp. were detected above bloom levels on May 1st. Domoic Acid results are not yet available for the month of May. 

Santa Cruz Municipal Wharf does not measure for Pseudo-nitzschia delicatissima group. 

Monterey Wharf

 Monterey Wharf water samples are not yet available for the month of May.  

Cal Poly Pier

Water samples were collected at Cal Poly Pier four times in the month of May. Pseudo-nitzschia seriata group and Pseudo-nitzschia delicatissima group were not detected in any water samples. Alexandrium spp. were detected at bloom levels in three of the four samples. Domoic Acid results are not yet available for the month of May.  

Stearns Wharf

Water samples were collected at Stearns Wharf four times in the month of May. Pseudo-nitzschia delicatissima group and Pseudo-nitzschia seriata group were detected above bloom levels throughout the month of May and Alexandrium spp. were detected above bloom levels on May 7th and 13th. Domoic Acid results are not yet available for the month of May. 

Santa Monica Pier

Water samples were collected at Santa Monica Pier three times in the month of May. Pseudo-nitzschia delicatissima group and Pseudo-nitzschia seriata group were detected above bloom levels on May 20th. Alexandrium spp. were not detected in any samples. Domoic Acid results are not yet available for the month of May.