October 27, 2021

With funding from the NOAA National Centers for Coastal Ocean Science, researchers from Washington Sea Grant, the Northwest Indian College and Washington Department of Fish and Wildlife will study shellfish-killing toxins

Over the last few decades, shellfish farms and natural shellfish populations in Washington State have suffered large losses due to blooms of harmful algae that are not traditionally monitored and whose toxic effects are poorly understood. Washington Sea Grant (WSG) researchers and collaborators recently documented the role of yessotoxins and identified other plankton species as being suspicious in these shellfish mortality events. However, natural resource managers and shellfish growers need more information to understand these species of shellfish-killing algae and how to protect shellfish from future blooms.

With funding from the NOAA National Centers for Coastal Ocean Science (NCCOS) Monitoring and Event Response for Harmful Algal Blooms (MERHAB) Research Program, WSG, the Northwest Indian College and the Washington Department of Fish and Wildlife have embarked on a new project to identify harmful algal blooms (HABs) that cause these shellfish mortality events, focusing on key aquaculture sites where shellfish illness and deaths have been observed in the past. The overall goal is to develop and optimize a monitoring program for these harmful algae and their toxins in Washington State.

Specifically, the researchers will study how the phytoplankton species that produce yessotoxins and other shellfish-killing toxins are distributed across the state and the concentrations at which these toxins cause harm to shellfish. The researchers will also establish a warning system to alert resource managers and shellfish farmers of when these toxins are occurring and educate shareholders about HAB risk and management.

These new initiatives will strengthen HAB monitoring programs that already occur in the state. SoundToxins — a program led by WSG and powered by diverse partnerships — currently monitors for phytoplankton that are known to harm humans, ecosystems and economic health.

“By keeping an eye on Puget Sound through the SoundToxins phytoplankton monitoring and research program, we were able to connect the observations of the shellfish producers with those of the SoundToxins partners. This led to the documentation that phytoplankton were in fact killing bivalve shellfish,” says Teri King, aquaculture and marine water quality specialist at Washington Sea Grant. “With this MERHAB funding from the NOAA National Centers for Coastal Ocean Science, we will be able to refine the science so that we can determine how much yessotoxin it takes to kill the shellfish and correlate that to phytoplankton cell counts. This will help farmers and natural resource managers forecast potential mortality events.”

To carry out this new project, the partners will sample phytoplankton and shellfish where HAB-related shellfish mortalities commonly occur at eight SoundToxins sites in Puget Sound and two sites on the outer coast. The researchers will integrate laboratory experiments with monitoring activities into ongoing programs that are routinely collecting plankton, shellfish and water chemistry samples. Working closely with shellfish companies, tribes and state agencies, they will establish cost-effective monitoring to provide early warning of shellfish-damaging HAB events. Real-time data sharing and “traffic light” maps showing critical threshold levels of shellfish-killing HABs will provide an early warning to shellfish growers and managers, allowing them to act quickly, thereby minimizing economic losses. Examples of actions by shellfish managers to reduce the impacts of HABs on their crops include harvesting early, slowing or stopping intake of seawater, or filtration.

This peer-based enhanced HAB monitoring program will rely heavily on collaboration from beginning-to-end with end users of this optimized early warning system — the monitoring partnerships of SoundToxins, the Northwest Indian College, state shellfish managers, tribes, and shellfish growers — helping them keep pace with expanding HAB impacts in Washington State. 

For more information, contact:

Teri King, Washington Sea Grant: guatemal@uw.edu
Carrie McCausland, Washington Department of Fish and Wildlife: Carrie.McCausland@dfw.wa.gov
Benjamin Anderson, Washington Department of Fish and Wildlife: Benjamin.Anderson@dfw.wa.gov
Barbara Lewis, Northwest Indian College: bjlewis@nwic.edu
Sierra Sarkis, NOAA National Centers for Coastal Ocean Science: sierra.sarkis@noaa.gov