Rapid Response Network

Coordinated by Ashleigh Epps, Washington Sea Grant; Rana Brown, Squaxin Island Tribe; and Julieta Martinelli, Washington Department of Fish and Wildlife

Contact: deadshellfish@uw.edu

About the Network

Shellfish have been an integral part of the life of Washington state Tribes for millennia, and for residents and visitors alike. The shellfish aquaculture industry in Washington State is the largest in the nation, generating 150 million in annual farmed bivalve sales. Over the past century, shellfish have transformed the state’s economic landscape, creating thousands of jobs in coastal communities. Additionally, shellfish provide an important ecological role to the surrounding ecosystems.

In June 2021, the region faced an unprecedented climatic event that led to high mortality in many shellfish species. An atmospheric heatwave coincided with the lowest low tides of the year (June 26-28, 2021), exposing intertidal and subtidal invertebrates to unusually high air temperatures. These anthropogenic changes (i.e., warmer ocean and air temperatures) are expected to persist and increase in frequency and intensity, suggesting that the threats that extreme weather events pose to shellfish are likely to continue.

Therefore, there was a need to create a Rapid Response Network for resource managers and shellfish industry members to prepare and stay uniformly informed about potential upcoming climate-induced shellfish mortality events. This also includes creating a Rapid Response Plan that aims to develop standardized sampling recommendations that can be used to both: (1) monitor non-harvest beaches to obtain baseline data; and (2) detect changes to shellfish communities over time due to climate-driven events.

Takeaways from the 2021 mortality event

  • Coastal sites largely avoided negative impacts due to increased wind and wave action compared to inner Puget Sound sites that are more protected.
  • Manila and native littleneck clams varied in observed conditions.
  • Olympia oysters, which tend to reside in the lower coastal zone, were less affected than Pacific oysters.
  • Pacific oysters were in poor condition in more southerly latitudes.
  • Species in the higher intertidal zones, such as barnacles, were in much worse condition than those found in the lower intertidal regions.
  • Species that could burrow further into the sediment (>15cm) were observed to be in better condition (i.e., butter clams) than those that burrowed shallower in the sediment (i.e., cockles).
  • Mortalities continued to be observed weeks after the event, likely due to prolonged heat stress.
  • Many of these species were likely reproductive at this time, which has resulted in decreased adult populations in some locations.

Observed climate-induced mortalities from 2021-present

Rapid Response Plan

Rapid Response Plan: Coming Fall 2025

Suggested priority species for surveys:

  • Manila clams (Venerupis philippinarum)
  • Native littleneck clams (Leukoma staminea)
  • Butter clams (Saxidomus giganteus)
  • Cockles (Clinocardium nuttallii)
  • Razor clams (Siliqua patula)
  • Macoma clams (Macoma spp.)
  • Pacific oysters (Crassostrea gigas)

Rapid Response Methods

1) Rapid survey developed by Swinomish Indian Tribal Community (SITC) (Note: cockle surveys only)

  • Use a GPS unit to walk the rough perimeter of the mortality area.
  • Select 2-3 areas to carry out a 50 m transect line
  • For each transect count all dead shells 1 m to the right, and 1m to the left of the transect. Think of this as a giant 2*50 m quadrat.
  • Repeat for as many 50 m transects as you can.
  • Use the transect calculation to estimate number of dead shells per m2, and for the total area estimated in the perimeter.

Example table that can be used for this method:

Example table for data collection according to the Swinomish Indian Tribal Community survey protocol

2) Semiquantitative method based on Raymond et al. (2022)

Google form to gather these data from scientists: SHELLFISH MASS MORTALITY RAPID SURVEY

For observations of large numbers of dead or dying invertebrates (e.g. after a series of very hot days, you visit your local beach or private tideland and notice a large number of dead oysters with their shells separated and gaping open).

Raymond et al. (2022) used a Post Heat Wave Rating (PHWR) survey to assess shellfish condition using a semi-quantitative rating scale. Scientists had to possess extensive local knowledge of a site in order to submit information. Their expert knowledge was used to assess what they were seeing relative to what they would consider typical based on their prior experience with specific sites and species at the same time of year.

Experts rated the condition of the animals according to the following scale:

1 = much worse than normal

2 = worse than normal

3 = normal

4 = better than normal

5 = much better than normal

3) Washington Department of Fish and Wildlife (WDFW) – Reporting Tool

Link to the reporting tool: SHELLFISH MASS MORTALITY REPORTING TOOL

For commercial shellfish growers: the shellfish and marine invertebrate mass mortality reporting tool helps WDFW understand how industry is impacted by these events; however, please note that this reporting tool does not supersede reporting requirements established as part of transfer permit conditions.

Toolboxes

Group name: Shellfish and Seaweed Biosecurity Health

Affiliation: Washington Department of Fish and Wildlife

About: You can find information about permitting, transfers, and AIS-related programs

Contact: Shellfish, aquatic invertebrate, and seaweed health and cultivation permitting | Washington Department of Fish & Wildlife

 

Group name: Shellfish – Information for the General Public

Affiliation: Washington State Department of Health

About: shellfish-safety map, biotoxins, preventing shellfish-related illnesses

Link: Shellfish | Washington State Department of Health

Contact: Shellfish Program Contacts | Washington State Department of Health

 

Group name: Michael Metzger’s Lab

Affiliation: Pacific Northwest Research Institute

About: Research on transmissible cancer in bivalves and related topics

Link: Metzger Lab – Pacific Northwest Research Institute

Contact: Metzger Lab – Pacific Northwest Research Institute

 

Group name: Chelsea Wood’s Lab

Affiliation: School of Aquatic and Fishery Sciences, University of Washington

About: Research on parasites of commercially important fish and oysters

Link: Wood Lab – ecology of parasites in marine and freshwater ecosystems

Contact: chelwood@uw.edu

Group name: Sound Toxins

Affiliation: Washington Sea Grant

About: monitoring program that provides early warning of harmful algal blooms

Link: SoundToxins — Home

Contact: soundtox@uw.edu, Michelle Lepori-Bui & Melissa Petrich

 

Group name: Biotoxin Monitoring

Affiliation: WA Department of Health

About: monitoring program that provides early warning of harmful algal blooms

Link: Biotoxin Beach Closures by County

Contact: biotoxins@doh.wa.gov

Company name: AquaTechnics Inc.

About: shellfish health and lab services for aquaculture

Link: Aquatechnics Inc.

Contact: ralph@aquatechnics.com

 

Company name: Sensoreal

About: A semi-quantitative, rapid test kit for PSP toxins in shellfish

Link: Sensoreal

Contact: hello@sensoreal.com

Group name: Pacific Shellfish Institute

About: This tool is used for research purposes only to observe oyster mortalities in triploid oysters during summer mortality events. Link to website.

Link: Shellfish Mortality Reporting Form

Contact: psi@pacshell.org

 

Name: Craig Norrie

Affiliation: University of Washington

About: This study looks at the environmental costs and benefits of using diploid or triploid seed for farming Pacific oysters.

Link: Research Article: Differential performance of diploid, mated triploid, and induced triploid Pacific oysters under varied environmental conditions: Insights into impacts of temperature, dissolved oxygen, and pCO2

Contact: cnorrie@uw.edu

What have we been up to?

Outreach

Slack

We have an online Slack channel where resource managers, industry members, agencies, and researchers can communicate about any current or upcoming climate-induced events that are causing or may cause mass shellfish mortalities. If you would like to be added to this channel, please email us at deadshellfish@uw.edu with your preferred email address to be added to the Slack channel, and we will send you a link. Visit Slack.com for more information about what a Slack channel is.

Conference presentations

  • Washington Sea Grant Shellfish Growers Conference (March 2024)
  • Pacific Coast Shellfish Growers Association (September 2024)
  • Washington Sea Grant Shellfish Growers Conference (February 2025)
  • Next presentation: Pacific Coast Shellfish Growers Association (September 2025)

Presentations from these conferences are available by request. Please contact deadshellfish@uw.edu to request one.

Surveying

Squaxin Island Tribe surveying, April 2, 2025. Photos by Ashleigh Epps, Washington Sea Grant.

Squaxin Island Tribe surveying, June 21, 2024. Photos by Ashleigh Epps, Washington Sea Grant.

The Rapid Response Network is in collaboration with University of Washington, Taylor Shellfish, Jamestown SK’lallam Tribe, Puget Sound Restoration Fund, Swinomish Indian Tribal Community, Skokomish Indian Tribe, Evergreen State College, and NOAA National Marine Fisheries Services.

Washington Department of Fish and Wildlife logoSquaxin Island Tribe logo