title: An unprecedented coastwide toxic algal bloom linked to anomalous ocean conditions.
abstract: A coastwide bloom of the toxigenic diatomPseudo-nitzschiain spring 2015 resulted in the largest recorded outbreak of the neurotoxin, domoic acid, along the North American west coast. Elevated toxins were measured in numerous stranded marine mammals and resulted in geographically extensive and prolonged closures of razor clam, rock crab, and Dungeness crab fisheries. We demonstrate that this outbreak was initiated by anomalously warm ocean conditions.Pseudo-nitzschia australisthrived north of its typical range in the warm, nutrient-poor water that spanned the northeast Pacific in early 2015. The seasonal transition to upwelling provided the nutrients necessary for a large-scale bloom; a series of spring storms delivered the bloom to the coast. Laboratory and field experiments confirming maximum growth rates with elevated temperatures and enhanced toxin production with nutrient enrichment, together with a retrospective analysis of toxic events, demonstrate the potential for similarly devastating ecological and economic disruptions in the future.
authors.affiliation: Joint Institute for the Study of the Atmosphere and Ocean University of Washington Seattle Washington USA.
authors.forename: Ryan M
authors.initials: RM
authors.lastname: McCabe
authors.affiliation: School of Oceanography University of Washington Seattle Washington USA.
authors.forename: Barbara M
authors.initials: BM
authors.lastname: Hickey
authors.affiliation: Ocean Sciences Department University of California Santa Cruz California USA.
authors.forename: Raphael M
authors.initials: RM
authors.lastname: Kudela
authors.affiliation: Northwest Fisheries Science Center, National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington USA.
authors.forename: Kathi A
authors.initials: KA
authors.lastname: Lefebvre
authors.affiliation: Northwest Fisheries Science Center, National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington USA.
authors.forename: Nicolaus G
authors.initials: NG
authors.lastname: Adams
authors.affiliation: Northwest Fisheries Science Center, National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington USA.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Bill
authors.affiliation: The Marine Mammal Center Sausalito California USA.
authors.forename: Frances M D
authors.initials: FM
authors.lastname: Gulland
authors.affiliation: Department of Fisheries and Oceans Institute of Ocean Sciences Sidney British Columbia Canada.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Thomson
authors.affiliation: Romberg Tiburon Center for Environmental Studies San Francisco State University Tiburon California USA.
authors.forename: William P
authors.initials: WP
authors.lastname: Cochlan
authors.affiliation: Northwest Fisheries Science Center, National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington USA.
authors.forename: Vera L
authors.initials: VL
authors.lastname: Trainer
keywords: Pseudo‐nitzschia australis; domoic acid; harmful algal bloom; toxin; upwelling; warm anomaly