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 (DA). As in March, C-HARM probabilities for blooms for April are highest from the Santa Barbara Channel north, offshore to nearshore, with high nearshore probabilities in the Southern California Bight. The persistency of this pattern over the last several months suggests model re-tuning may be necessary, although observations at the piers do align with this pattern for the most part (keeping in mind we have no offshore observations with which to validate the model). HABMAP observations of Pseudo-nitzschia spp. abundance indicate bloom conditions for mostly "seriata" (toxigenic) and to some extent "delicatissima" (non-toxigenic) size-classes at all the pier stations from, intensity building as we move southward (just as was the pattern in March). P. seriata size class abundances were in the 30-40,000 cells per Liter range for Southern California sights, although no data are yet available for Scripps Pier in San Diego. CDPH sampling in April shows highest Pseudo-nitzschia percent composition in the San Pedro Basin (LA area), Santa Barbara Channel, central coast near San Luis Obispo, and northern Monterey Bay near Santa Cruz, a similar pattern to March.

Domoic Acid - C-HARM also tells us where DA might be more likely to occur at high levels. April observations of DA  are not yet available for any of the HABMAP pier sampling sites. Probabilities of particulate DA (pDA) are most pronounced in the nearshore regions of the North Coast, pockets outside SF Bay and Monterey Bay, around Pt Conception where spring westerly to northwesterly winds are likely producing high wind stress curl and upwelling nutrient-rich waters that fuel blooms, and throughout the nearshore and offshore waters of the Southern California Bight. High cellular DA (cDA) probabilities in the Bight and along the central coast are consistent with the predicted Pseudo-nitzschia growth in that area, where cDA production might also be peaking. The three of the four sea lion strandings from DA toxicosis in the month of April were recorded in the LA and Long Beach area, consistent with high probabilities of pDA (and cDA) in those zones and with high observed abundance of the P. seriata size class (more toxigenic group of Pseudo-nitzschia) at Newport Beach Pier and Santa Monica Pier. The sea lion stranding on the central coast is consistent with high probabilities of pDA (and cDA) and elevated measures of P. seriata size class at Stearns Wharf and Cal Poly Pier.

Alexandrium - HABMAP records for Alexandrium at pier sites show little activity from January to April 2019, which is consistent with little or no increases in the relative abundance of this dinoflagellate as measured by the CDPH volunteer phytoplankton monitoring network. However, as we moved into May, things got interesting as evidenced by the high % composition of Alexandrium from CDPH in offshore Monterey Bay waters.... stay tuned.

Santa Cruz Wharf

Water samples were collected four times at Santa Cruz Municipal Wharf in the month of April. Pseudo-nitzschia seriata group was detected below bloom levels and Alexandrium spp. were detected above bloom levels on April 24th. Domoic Acid results are not yet available for the month of April. 

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

Monterey Wharf

Water samples were collected at Monterey Wharf four times in the month of April. Pseudo-nitzschia seriata group and Pseudo-nitzschia delicatissima group were detected above bloom levels on April 3rd, 17th, and 24th. Alexandrium spp were not detected in any of the April samples. Domoic Acid results are not yet available for the month of April.  

Cal Poly Pier

Water samples were collected at Cal Poly Pier three times in the month of April. Pseudo-nitzschia seriata group was detected above bloom levels on April 7th. Pseudo-nitzschia delicatissima group and Alexandrium spp. were not detected in any of the samples. Domoic Acid results are not yet available for the month of April.  

Stearns Wharf

Water samples were collected at Stearns Wharf five times in the month of April. Pseudo-nitzschia delicatissima group and Pseudo-nitzschia seriata group were detected above bloom levels on April 16th, 22nd, and 29th. Alexandrium spp. were detected below bloom levels on April 16th and 29th. Domoic Acid results are not yet available for the month of April. 

Santa Monica Pier

Water samples were collected at Santa Monica Pier five times in the month of April. Pseudo-nitzschia delicatissima group and Pseudo-nitzschia seriata group were detected above bloom levels on April 15th and 22nd. Domoic Acid results are not yet available for the month of April. 

Scripps Pier

Scripps Pier Pseudo-nitzschia spp., Alexandrium spp., and domoic acid results are not yet available at this time.