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Puget Sound Indicators
Area of harvestable shellfish beds
Basics
Healthy Human Population
Shellfish Beds
Indicator
Area of harvestable shellfish beds
Vital Sign Indicator
Acre (acres)
/

Achieve an annual net gain of at least 500 acres approved for shellfish harvesting, based on a three-year rolling average.

Target fact sheet

Memo to Science Panel with rationale

Scott Berbells
Scott.Berbells@DOH.WA.GOV
Washington State Department of Health
Contributing Partners
Last Updated
1/29/2024 1:50:46 PM
Map
Points identify Shellfish Growing Areas in Puget Sound where the total harvestable acres changed in 2023, 2022, or 2021. Green points indicate an upgrade in acres; gray points indicate a downgrade in acres. Point locations are centered on the Growing Area and do not represent the location of change. Zoom in to see the Commercial Shellfish Growing Area boundary and classification summary.
WA Department of Health Office of Environmental Health and Safety, Commercial Shellfish Map Viewer
Description

This indicator tracks changes in the classification of harvestable shellfish beds in Puget Sound. The Washington State Department of Health classifies 115 shellfish growing areas in Puget Sound to assure that harvested shellfish are safe to consume. The data collected for the classification process represent the conditions that dictate shellfish harvest, and their trends provide information on marine water quality in Puget Sound.


Vital Sign Indicator Chart
Area of harvestable shellfish beds
By: Classification change

Area (acres) of harvestable shellfish beds where the Washington Department of Health classification has changed. Upgrades in classification mean that water quality has improved, allowing for fewer restrictions on shellfish harvest. Downgrades mean there are either more restrictions on when shellfish may be harvested, or harvest is not allowed. 

The Puget Sound nearshore is home to an amazing abundance of oysters, clams, mussels, and other shellfish that provide opportunities for recreational shellfish harvest and form the basis for a multi-million dollar natural resource-based industry that supports thousands of jobs.

Key Vital Sign Indicator Results
  • Commercial shellfish growing areas in Puget Sound cover roughly 260,000 acres. About 86% (224,600 acres) of this area is suitable for harvest.
  • In 2022 the Leadership Council approved a new target to achieve a net gain of at least 500 acres approved for shellfish harvesting every year, based on a three-year rolling average. The net change in harvestable shellfish beds in 2023 for all of Puget Sound was 432 acres. The three-year average (2021-2023) net change was -146 acres.
  • In 2023 improved water quality conditions in four growing areas resulted in classification upgrades across 476 acres. That same year, Washington Department of Health (DOH) needed to downgrade classifications in two growing areas. A total of 44 acres were downgraded resulting in more restrictions on shellfish harvest. For more information, see the Interpretation of Results section.
  • Since 2007 more acres of shellfish growing areas have been upgraded than downgraded. The positive trend reflects state, tribal, and local investments in effective pollution identification and correction programs. However, in both 2021 and 2022 more acres were downgraded than upgraded. This recent pattern is concerning and highlights the ongoing challenge to identify and correct nonpoint source pollution that impacts water quality in the nearshore.
  • The upgrades in growing area classifications since 2007 were dramatically offset by the 2011 downgrade of the Samish Bay shellfish growing area (4,037 acres). This downgrade impacted the overall net acreage gained and slowed progress toward the previous 2020 recovery target.
Methods
Monitoring Program

Washington State Department of Health, Shellfish Growing Areas Program

Data Source

Washington State Department of Health, Office of Environmental Health and Safety

Shellfish Growing Area Annual Reports

The Washington State Department of Health (DOH) classifies 115 different shellfish growing areas in Puget Sound, covering roughly 250,000 acres. Growing area classifications are assigned based on the results of a shoreline survey, marine water quality sampling, and analysis of pollutants in the area.

Commercial growing area classifications:

  • Approved
  • Conditionally Approved
  • Restricted
  • Prohibited

Upgrades in classification mean that water quality has improved, allowing for fewer restrictions on shellfish harvest. Any shellfish beds classified as conditionally approved, restricted, or prohibited whose status is upgraded, results in newly harvestable acres and are counted toward the recovery target.

Downgrades mean there are either more restrictions on when shellfish may be harvested or no harvest is allowed at any time. Downgrades are generally caused by fecal bacteria or other pollutants in the water that make shellfish unsafe to eat.

The shellfish harvest area classification process is defined in federal rules and adopted in state regulations. DOH implements the rules at the state level. The purpose of the DOH Shellfish Growing Areas Program is to assure that harvested shellfish are safe to consume. This also includes making certain that pollution sources are continually assessed and marine water quality monitored around every classified harvest area. The data collected for the classification process represent the conditions that dictate shellfish harvest, and their trends provide information on marine water quality in Puget Sound.

DOH samples more than 1,700 marine water stations between 6 and 12 times each year for fecal coliform bacteria, salinity, and temperature. A minimum of 30 of the most recent samples from each marine water station are used to classify each shellfish harvesting area. In addition, shoreline pollution sources, including wastewater treatment plants, individual on-site sewage systems, marinas, farms, and any other activity with the potential to impact the shellfish area, are evaluated periodically and results are integrated in the classification process.

Critical Definitions

Classifications and their definitions:

  • Approved: commercial harvest for direct marketing. Sanitary survey shows the area is not subject to contamination that presents an actual or potential public health hazard.
  • Conditionally Approved: opened or closed for predictable periods of time. Meets Approved criteria some of the time, but does not during predictable periods. The length of closure is based on data that show the amount of time it takes for water quality to recover and again meet Approved criteria.
  • Restricted: cannot be marketed directly and must be transplanted to Approved growing areas for a specified amount of time. Meets standards for an Approved criteria, but the sanitary survey indicates a limited degree of pollution from non-human sources. Harvest must be transplanted to Approved growing areas to allow shellfish to naturally cleanse themselves of contaminants before they can be marketed.  
  • Prohibited: closed to commercial and recreational harvest. When the sanitary survey indicates harmful substances may be present in concentrations that pose a health risk. Growing areas that have not undergone a sanitary survey are also classified as prohibited.
Interpretation of Results

The total net change in harvestable shellfish beds for all of Puget Sound in 2023 was 432 acres. Click here (or download from Datasets below) for a list of all upgrades and downgrades since 2007.

In 2023 Washington Department of Health (DOH) upgraded the harvest classification at four growing areas:

  • Dyes Inlet in Kitsap County (50 acres from Prohibited to Approved)
  • Swinomish in Skagit County (137 acres from Prohibited to Approved)
  • Burley Lagoon in Pierce County (57 acres from Restricted to Conditional)
  • Budd Inlet in Thurston County (232 acres from Prohibited to Approved)

In 2023 DOH needed to downgrade two growing areas:

  • Hood Canal #5 in Mason County (14 acres from Approved to Conditional)
  • Hood Canal #6 in Mason County (30 acres from Approved to Prohibited)

In 2022 DOH upgraded the harvest classification at just two growing areas:

  • Henderson Bay in Pierce County (18 acres from Restricted to Approved)
  • Henderson Inlet in Thurston County (26 acres from Restricted to Conditional)

In 2022 DOH needed to downgrade five growing areas:

  • Port Susan in Snohomish County (317 acres from Approved to Prohibited)
  • Poverty Bay in King County (68 acres from Conditional to Prohibited)
  • Drayton Harbor in Whatcom County (42 acres from Approved to Conditional)
  • Vaughn Bay in Whatcom County (40 acres from Conditional to Prohibited)
  • Henderson Inlet in Thurston County (11 acres from Approved to Conditional)

Downgrades in 2022 at Port Susan and Drayton Harbor follow downgrades at these growing areas in 2021 (183 acres downgraded at Port Susan and 693 acres downgraded at Drayton Harbor). Both areas are impacted by significant freshwater stream flows that carry pollution from sources throughout the watershed into the nearshore.

Since 2007, the baseline reference year, sanitary conditions in some shellfish harvest areas improved enough to change their classifications for the better, and they were upgraded (cumulative total was 14,981 acres as of January 2024). However, others changed for the worse and were downgraded (cumulative total of 8,760 acres, over 4,000 acres of which was in Samish Bay). The net result was an increase of 6,221 acres with fewer restrictions on shellfish harvest for all of Puget Sound.

More than 35,000 acres (14%) of shellfish harvest areas are classified as Prohibited due to the proximity of pollution sources or poor water quality. Shellfish harvest on most of this acreage is prohibited because of a nearby wastewater treatment plant outfall. Marinas and nonpoint source pollution, such as excess fertilizers from agricultural lands, oil and toxic chemicals from urban runoff, and bacteria and nutrients from livestock, pet wastes and faulty septic systems, are other factors that could impact public health and prohibit shellfish harvest.

Table 1. Classification and acreage of shellfish growing areas in Puget Sound (as of January 2024). Source: Washington State Department of Health, Office of Environmental Health and Safety
Classification Definition Acreage

Approved: commercial harvest for direct marketing

Sanitary survey shows the area is not subject to contamination that presents an actual or potential public health hazard.

 148,737

Conditionally Approved: opened or closed for predictable periods of time

Meets Approved criteria some of the time but does not during predictable periods. The length of closure is based on data that show the amount of time it takes for water quality to recover and again meet Approved criteria.

 12,364

Restricted: cannot be marketed directly and must be transplanted to Approved growing areas for a specified amount of time

Meets standards for an Approved criteria, but the sanitary survey indicates a limited degree of pollution from non-human sources. Harvest must be transplanted to Approved growing areas to allow shellfish to naturally cleanse themselves of contaminants before they can be marketed.

 63,490

Prohibited: closed to commercial and recreational harvest

When the sanitary survey indicates harmful substances may be present in concentrations that pose a health risk. Growing areas that have not undergone a sanitary survey are also classified as prohibited.

 35,099
Total   259,690

 

Pollutants, marine pathogens, and naturally occurring marine biotoxins (paralytic shellfish poison or domoic acid) can all restrict shellfish harvest opportunities (Dethier 2006). Shoreline pollution sources, including wastewater treatment plants, failing onsite sewage systems, marinas, farms and animal waste, and other activities can negatively impact the shellfish areas and lead to human health risks. Many commercial shellfish beds in Puget Sound have been closed due to pollution and bacterial contamination and shellfish harvest is prohibited along the entire eastern shore of Puget Sound from Tacoma to Everett. 

Downgrades and closures of shellfish harvest areas have been offset since 2007, the indicator's baseline reference year, by classification upgrades largely due to better pollution controls and related improvements in water quality, including:

  • Creation of Shellfish Protection Districts and the development and implementation of closure response plans. 
  • Effective pollution identification and correction programs.
  • Development and implementation of on-site sewage system management practices.
  • Control of boaters' waste.

Since 2011, DOH has invested over $35 million in grants around Puget Sound funded by the Environmental Protection Agency’s (EPA) National Estuary Program to help improve water quality. These grants support pollution identification and correction projects, on-site septic system management programs, research, and shellfish protection districts. These efforts combined with other local and state funds have gone a long way to protect and improve water quality around Washington’s shellfish beds.

Although the Sound-wide trend in improvement is positive, many factors affect the long-term ability to protect and improve harvestable shellfish beds. The Shellfish Beds Implementation Strategy outlines key barriers to improvement and potential approaches to increase acreage safe for shellfish harvest. To date, implementation of effective pollution identification and correction (PIC) programs, agricultural best management practices, and on-site sewage system operation and maintenance programs have resulted in the correction of pollution sources. These corrections have led to improved water quality and upgraded shellfish acreage.

The significant downgrade of the Samish Bay shellfish growing area in 2011 impacted the overall net acreage gained and slowed progress toward the 2020 target. Through the work of the Clean Samish Initiative, many improvements have been recorded throughout the watershed. The Clean Samish Initiative is a coalition of federal, state, and county governments, Indian tribes, non-governmental organizations, shellfish growers, and private citizens dedicated to reducing fecal coliform pollution in the Samish Bay Watershed. This successful, collaborative effort continues its pollution abatement work, with special emphasis on linking landowners with resources to help them reduce the risk of pollution from their property. Challenges remain, however. The Samish River directs stream flows from a large watershed into Samish Bay. These freshwater flows also carry pollution accumulated from a variety of sources in the watershed which can lead to unsafe conditions for shellfish harvest in the Bay.

Dethier, M.N. 2006. Native Shellfish in Nearshore Ecosystems of Puget Sound. Puget Sound Nearshore Partnership Report No. 2006-04. Published by Seattle District, U.S. Army Corps of Engineers, Seattle, Washington.

Datasets

The Puget Sound Partnership believes in the transparency and accessibility of the data used to address puget sound indicators. These data are provided by contributing partners to the Partnership and are made publicly available through the Puget Sound Info site. These data are available on an "as is" basis and the Partnership is not responsible for any errors, omissions, or inaccuracies. Please acknowledge the monitoring program and data source when using these data and obtain permission from the Vital Sign Indicator Reporter to use these data in a publication.

Puget Sound Shellfish Beds Annual Upgrades and Downgrades
Uploaded On
1/29/2024
File Type
Excel (XLSX)
Description
Table of the annual changes in classification of harvestable shellfish beds in Puget Sound. Data source: Washington State Department of Health, Office of Environmental Health and Safety
Reporting Guidance
Reporting Instructions

Not applicable to Vital Sign indicators

Subcategories
Name
Classification change
Upgrades, Downgrades, Cumulative net change