Human Health
Olympic Coast

close up of Ciguatera growth on algae
Bivalves, like the razon clam shown here, are filter feeders and can concentrate toxins that can lead to paralytic shellfish poisoning (PSP) or amnesic shellfish poisoning (ASP) in mammals. Credit: OCNMS, NOAA

Why is it a concern?

Olympic Coast National Marine Sanctuary is remote from population and industrial centers that are sources of contaminants and pathogens that may impact human health.  Natural phenomena, specifically harmful algal blooms (HABs), do pose a risk to humans through consumption of contaminated shellfish, particularly bivalves. During HAB events, filter feeding organisms, such as clams and mussels, can concentrate toxins originating in microscopic algae, rendering the shellfish toxic to consumers. For centuries, consumers of bivalves in the Pacific Northwest have known about paralytic shellfish poisoning (PSP), a condition caused by saxitoxins produced by planktonic dinoflagellates. In 1991, domoic acid, a neurotoxin produced by diatoms in the genus Pseudo-nitzschia that causes amnesic shellfish poisoning (ASP), was first detected in clams on Washington’s outer coast. Additional planktonic sources of biotoxins in local waters are being discovered and investigated today. 

Since monitoring was initiated in the early 1990’s, biotoxins in shellfish have exceeded the state’s allowable levels on average once or twice a year on Washington’s outer coast and have led to shellfish closures. The state Department of Health has received no reports of shellfish poisoning in humans on the outer coast since 1991, although exposures have been reported from other areas in Washington.


Overview of Research

Research conducted by sanctuary scientists and partners provides critical information to address existing and emerging resource conservation and management issues. The Overview of Research highlights some, but not necessarily all, of the research activities completed or ongoing at the sanctuary.

Project Name PI and contacts Links

Blue Water Task Force

Surfrider Foundation

Shellfish Program

Washington State Department of Heath

Northwest Fisheries Science Center Harmful Algal Blooms Program

Vera Trainer, NMFS

Olympic Region Harmful Algal Bloom (ORHAB) partnership

Daniel Ayers, WA Dept. of Fish and Wildlife


Science Needs and Questions

There is a general need for improved characterization of nearshore oceanographic conditions in OCNMS.  Currently, they are poorly characterized with respect to temporal and spatial dynamics and associated ecological processes. Specifically, this includes questions about initiation, distribution and persistence of HABs.

  • Can existing oceanographic data, including OCNMS mooring data, be used as a predictive tool for HAB events?
  • Are there oceanographic parameters that correlate with HAB events for which increased monitoring is needed?
  • What is the role of the Juan de Fuca Eddy in initiation of HAB events?
  • What conditions correlate with or trigger production of biotoxins in HAB species?

Education and Outreach Material

Washington Department of Health, Recreational Shellfish Harvest Closure information

Woods Hole

National Marine Fisheries Service - Water quality

National Marine Fisheries Service - The Hunt for Killer Algae

National Marine Fisheries Service - Harmful Algal Blooms

Washington SeaGrant - Harmful Algal Blooms

Washington SeaGrant - Shellfish in Washington


Juan de Fuca Eddy Steering Committee. 2004. The Big Eddy - Proceedings of the Western Juan de Fuca Ecosystem Symposium. Western Juan de Fuca Ecosystem Symposium 10-11 May 2004, Institute of Ocean Sciences, Sidney, B.C. Canada. Canadian Parks and Wilderness Society. 141 pp.

Trainer, Vera L., Barbara M. Hickey, and Rita A. Horner. 2002. Biological and physical dynamics of domoic acid production off the Washington coast. Limnology and Oceanography 47.5: 1438-1446.