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Harmful algae - Monitoring Oregon's coastal harmful algae

red tide
Phytoplankton bloom

Oregon's Harmful Algal Bloom monitoring projects exist thru external grants. After a 2005 coast wide shellfish harvesting closure due to Domoic Acid (DA), ODFW requested rapid response funding from the NOAA Center for Sponsored Coastal Ocean Research (CSCOR) that enabled Oregon to initiate a monitoring program similar to Washington State's ORHAB (Olympic Region Harmful Algal Bloom) project.

In 2006, ODFW in collaboration with Oregon State University, University of Oregon and the NOAA Northwest Fisheries Science Center were awarded a five year nearly $2.3 million competitive grant from the NOAA CSCOR Monitoring and Event Response for Harmful Algal Bloom (MERHAB) research program to develop an integrated harmful algal bloom (HAB) monitoring and event response program. This program, MOCHA, begun collecting data in 2007. ODFW staff, in conjunction with Oregon Department of Agriculture, monitor 10 sites along the coast of Oregon for any potential signs of the phytoplankton that cause Domoic Acid (Pseudo-nitzschia sp.) and Paralytic Shellfish Poisoning (Alexandrium sp.). This first funded project ended in 2012. Since that initial project, ODFW has secured two more grants (2016-2022 and 2023) to continue the project. The data collected by this project is used to develop an early warning system which enables coastal shellfish managers along the PNW to know if shellfish could be impacted by a deadly toxin.

Harmful Algae Blooms (HAB’S)

  • Over 300 species of phytoplankton have been implicated in causing harmful algal blooms.
  • While most HABs are harmless, over 80 phytoplankton species may produce toxins that are harmful to humans and marine life.
Domoic Acid explanation

ODFW and ODA biologists discuss Oregon’s biotoxins and HAB’s


  • Phytoplankton
    The Latin roots of phytoplankton translate to "phyto" meaning plant and "plankton" meaning drifter.
  • Phytoplankton is a primary producer responsible for approximately 50 percent of earth's oxygen production.
  • There are an estimated 5,000 marine species.
  • Phytoplankton are the base of the oceans food web and help sustain all marine life.
  • Usually single celled organisms, though they commonly form colonies.
  • Cells range in size from two microns to two millimeters.
  • Phytoplankton reproduce by sexual or asexual reproduction.
  • Use photosynthesis to convert light, carbon, and nutrients into energy.
  • Capable of living in a wide variety of marine environments.

Phytoplankton Species commonly found in Oregon and their associated toxins
(Click on images to see larger)

Pseudo-nitzachia causes: Amnesic Shellfish Poisoning (ASP) caused by the production of domoic acid
Dinophysis  causes:
Diarrhetic Shellfish Poisoning (DSP) 
Alexandrium causes: Paralytic Shellfish Poisoning (PSP)

ODFW scientist grabs water sample from surf 
ODFW scientist grabs water sample from surf 

Phytoplankton samples are collected weekly at the following sites: Clatsop beaches (3), Cannon Beach (1), South Beach (1), Bastendorff Beach (1) and Gold Beach (1).

Sampling for phytoplankton consists of testing sea surf water by the two following methods:

  1. Whole Water Sample - This sample is taken from the surf using a five gallon bucket to first collect the water. After the sand settles a small eight oz sample jar is filled. A temperature and salinity reading is taken, the jar is labeled and then prepared to be sent back to the lab for analysis.
  2. Net Tow Sample - This sample is taken using a phytoplankton net to concentrate what plankton are in the water. The net is made of a selective material allowing the sea water to escape while trapping the phytoplankton. The net can either be towed through the surf for a short amount of time or the sampler may pour a bucket or two of water through the top end to collect the sample. The sample is then placed in a container, labeled and sent to the lab.


Back at the lab, internationally trained staff receives and prepares the samples for analysis. Using a light microscope, concentrated samples are viewed to determine the presence of Pseudo-nitzschia sp. and Alexandrium sp. This gives staff a quick idea of what phytoplankton is abundant along the coast. Staff then tests the whole water samples using a 0.1 ml nano-plankton chamber. Any Pseudo-nitzschia sp., Alexandrium sp. or other variety of phytoplankton are recorded and quantified. The results are then checked against acceptable levels that were developed by the ORHAB project and action is taken if necessary.

Program goals

Through this monitoring, ODFW's goals are to:

  • Mitigate impacts of HAB's events to local economies.
  • Reduce human health impacts caused by HAB's.
  • Provide an early warning system for HAB events.
  • Further our knowledge of ocean health.
  • Fill a data gap in Oregon's key transition zone in West Coast oceanography and the Ocean Observing System.
  • Combine data from oceanographic research with data from ongoing plankton and shellfish monitoring programs.

Groups of interest

NANOOS Harmful Algal Blooms- Harmful Algal Bloom Information
NOAA's Harmful Algae Bloom Page - Harmful Algae: Red Tide
Oregon Department of Agriculture (ODA) - ODA Food Safety Division Shellfish safety closures


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