2022 Harmful Algal Bloom - Mass Mortality Event, San Francisco Estuary

This data package documents observations associated with a harmful algal bloom (HAB) of Heterosigma akashiwo in the San Francisco Estuary that began in July of 2022, which resulted in a widespread mass mortality event affecting fishes and invertebrates. The dataset compiles mortality observations from multiple sources, including community-science platforms (e.g., iNaturalist), non-profit reporting portals, agency hotlines, and agency field records. Records were synthesized to reconstruct the spatial and temporal progression of the event and to characterize affected taxa. These data provide a georeferenced record of species-specific mortality during a large-scale HAB event and may be used to support analyses of bloom impacts, species vulnerability, spatial distribution of mortality, community-science data integration, and disturbance-response planning. The dataset also serves as a case study demonstrating the utility of community-generated observations for documenting rapid-onset ecological disturbances.