Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 7447
Title: Hindcasts of harmful algal bloom transport on the Pacific Northwest coast
Author: S. N. Giddings, P. MacCready, B. M. Hickey, N. S. Banas, K. A. Davis, S. A. Siedlecki, Vera L. Trainer, R. Kudela, R. Pelland, Thomas P. Connolly
Publication Year: 2014
Journal: Journal of Geophysical Research
Volume: 119
Pages: 2439-2461
Keywords: harmful algal bloom,forecasting,Pacific Northwest

Harmful algal blooms (HABs) pose a significant threat to human and marine organism health, and negatively impact coastal economies around the world. An improved understanding of HAB formation and transport is desired to improve forecasting skill. A realistic numerical simulation of the US Pacific Northwest region is used to investigate transport pathways from known HAB formation hotspots to the coast. We show that transport pathways are seasonal with transport to the WA coast from a northern source (the Juan de Fuca Eddy) during the summer/fall upwelling season and from a southern source (Heceta Bank) during the winter/early spring due to the predominant wind driven currents. Interannual variability in the northern source is related to the degree of wind intermittency with more robust transport during years with more frequent relaxation/downwelling events. The Columbia River plume acts to mitigate HAB transport to the coast as the plume front blocks on-shore transport. The plume’s influence in the along-coast direction is variable although critical in aiding transport from the southern source to the WA coast via plume entrainment. Overall transport from our simulations captures all but one observed HAB beach landing from 2004-2007 (characterized by Pseudo-nitzschia cell abundance); however, numerous false positives occur. We show that incorporating phytoplankton biomass results from a coupled biogeochemical model reduces the number of false positives and thus improves our HAB predictions. 


Physical and biological data are used to provide a hindcast of harmful algal blooms on the Washington State coast.

Theme: Sustainable, safe and secure seafood for healthy populations and vibrant communities
Foci: Provide scientific support to ensure safe seafood for healthy populations and characterize how human activities and climate affect risks from pathogens, chemical contaminants and biotoxins
Support collaborative community-based data collection, dissemination, and analysis for fishers, fisheries management, science, marketing, seafood safety, and education
Official Citation:

Giddings, S. N., P. MacCready, B. M., Hickey, N. S. Banas, K. A. Davis, S. A., Siedlecki, V. L. Trainer, R. M. Kudela, N., A. Pelland, Connolly, T.P. 2014. Hindcasts of potential harmful algal bloom transport pathways on the Pacific Northwest coast, J. Geophys. Res. Oceans, 119, 2439–2461, doi:10.1002/2013JC009622.