California Harmful Algal Bloom Bulletin

The purpose of this product is to give the public and resource managers a quick outlook of recent and future risk to toxic algal blooms in the State of California. Monthly to bi-monthly reports will synthesize model output, near real-time observations, and public health alerts to provide a more complete picture of the regional variability in harmful algal blooms, such as those caused by the diatom Pseudo-nitzschia spp. and its neurotoxin, domoic acid. The California Harmful Algae Risk Mapping (C-HARM) system creates daily nowcasts and three-day forecasts of this risk through simulations of the physical circulation using a Regional Ocean Model System (ROMS) to predict water temperature, salinity, upwelling, advection. ROMS outpus is merged with with optical "ocean color" information derived from NASA satellite imagery to then derive the probability of a toxic HAB even at each pixel. C-HARM is thus a spatially explicit prediction of the risk of Pseudo-nitzschia blooms and domoic acid events. Nearshore HABMAP monitoring funded by SCCOOS and CeNCOOS provides a near real-time picture of which HABs might be developing in the very nearshore environment. These nearshore data do not always correspond with what C-HARM predicts for the open coast. C-HARM output may be more closely correlated with marine mammals that strand along the coast due to "domoic acid toxicosis" (Anderson et al. Harmful Algae, 2016). Maps of DA-related stranding cases are displayed in the bulletin to allow a side-by-side comparison. Researcher tools for HABs are experiencing a renaissance, and we expect to highlight many more observations from technologies such as the Environmental Sample Processor, Imaging Flow Cytobot, and next-generation genetics analyses, as they become available, to flesh out our view of surface and subsurface HAB activity in coastal California. The HAB Bulletin will also highlight information on other potentially harmful phytoplankton, such as Alexandrium spp. (which can cause paralytic shellfish poisoming), Dinophysis (diarrhetic shellfish poisoning), and even the benign "red tides" caused by Lingoludinium polyedra.

May-June Bulletin

April-May Bulletin