Recent Progress: Increase
Ten Chesapeake Bay tributaries have been selected for oyster reef restoration: Harris Creek, the Little Choptank, Tred Avon, upper St. Mary’s and Manokin rivers in Maryland, and the Great Wicomico, Lafayette, Lower York, Lynnhaven and Piankatank rivers in Virginia. The Sustainable Fisheries GIT approved the Eastern Branch of the Elizabeth River in Virginia as an eleventh "bonus" tributary in 2020.
While scientists have developed restoration plans for all ten tributaries, each of these tributaries is at a different level of progress in a process that involves developing a tributary restoration plan, constructing and/or seeding reefs, and then monitoring and evaluating restored reefs. As of the end of 2022, seven of the ten originally selected tributaries have been restored (Harris Creek, the Little Choptank River, upper St. Mary’s River and the Tred Avon River in Maryland and the Lafayette, Piankatank and Great Wicomico rivers in Virginia), as well as the eleventh “bonus” tributary, the Eastern Branch of the Elizabeth River. Restoration work is underway in the remaining three tributaries under this goal (the Manokin River in Maryland and the lower York and Lynnhaven rivers in Virginia).
Following reef construction and seeding, monitoring and evaluation will take place at three- and six-year intervals, continuing beyond 2025. These monitoring activities determine the overall success of the restoration activity by tracking success at recruiting new oysters, survival in the early stages after settlement or planting, natural mortality, disease status, growth, reproduction and shell accumulation. More information about monitoring and evaluation protocols, frequency and success metrics can be found in Restoration Goals, Quantitative Metrics and Assessment Protocols for Evaluating Success on Restored Oyster Reef Sanctuaries from the Oyster Metrics Workgroup and in the 2022 Chesapeake Bay Oyster Restoration Update.
Outlook: On Course
The Oysters Outcome is on course and is expected to be met by 2025, although monitoring and evaluation of some of the oyster reef restorations will continue past 2025. In fact, large-scale oyster restoration in Chesapeake Bay has become an internationally recognized success story. Scientists and resource managers from Europe, Asia and Australia have visited to learn about the effort, and National Oceanic and Atmospheric Administration (NOAA) staff have travelled nationally and internationally to describe the project.
According to the Maryland and Virginia Oyster Restoration Interagency Teams, partners have invested nearly $87 million in oyster restoration in Chesapeake Bay tributaries over the past ten years. This includes reef construction only; costs such as benthic surveys to assess the health of the bottom of waterways, planning, permitting, and monitoring are not reflected.
Oyster Reef Restoration Progress Dashboard
According to the 2022 Chesapeake Bay Oyster Restoration Update, four Maryland tributaries (Harris Creek, the Little Choptank River, upper St. Mary’s River and the Tred Avon River) of the five Maryland tributaries in this outcome have been restored. Restoration work in the Manokin River started in 2021.
- Harris Creek’s restoration work was completed in 2015 with a total of 348 acres of reefs restored. In 2017 and 2018, several reefs received a second planting of oyster larvae attached to shells, called spat-on-shell. As of 2021, all three- and six-year post-restoration monitoring is complete. Monitoring results show that the restored reefs are largely successful. For example, all 14 six-year-old reefs monitored in Harris Creek in winter 2020-21 met the Oyster Metrics minimum threshold success criteria for oyster density and biomass, and 86% met the Oyster Metrics higher target criteria for these characteristics.
- The Little Choptank River’s restoration work was completed in 2020 with a total 358 acres of reefs restored, slightly more than in Harris Creek. 100% of six-year-old reefs met at least the ideal target density criteria for success. These reefs met additional criteria: They had oysters from multiple year classes and had sufficient shell substrate to persist into the future.
- The Tred Avon River’s restoration plan initially called for 147 acres of reefs to be present in the sanctuary, but this was later reduced to 130 acres. This work was completed in 2021. In the fall of 2021, monitoring showed that 100% of six-year-old reefs met the minimum success criterion for the density of oysters, while 50% met the ideal target density criteria. 100% of the six-year-old reefs met the multiple year class and shell budget success criteria.
- The upper St. Mary’s River’s restoration plan calls for 60 acres of restored reefs. Thirty-five acres of healthy, high-density oyster reefs already meet those standards. Restoration work started in 2021. Hatchery-produced seed were added to 16 acres of reef (seed-only reefs) using spat-on-shell. Additionally, Maryland DNR constructed nearly nine acres of reefs from stone substrate that were seeded with spat-on-shell in 2022. The river is considered initially restored.
- The Manokin River’s restoration plan calls for 441 acres of reefs to be restored. Restoration work started in 2021, and as of the end of 2022, 45 acres have been completed. The Manokin River Restoration Blueprint requires active restoration of the largest number of acres within any of the tributaries slated for restoration. Restoration work here will likely take until 2025.
According to the 2022 Chesapeake Bay Oyster Restoration Update, three Virginia tributaries have been restored toward the ten tributaries outcome (the Lafayette, Piankatank and Great Wicomico rivers). Restoration work is well underway in the remaining two tributaries, the Lower York and Lynnhaven rivers.
- Lafayette River’s restoration work was completed in 2018, which made it it the first river in Virginia to be considered complete under the ten tributaries outcome. The tributary is now in the monitoring phase. The Lafayette River’s restoration plan called for 80 acres of restored reefs, which was later revised to 82 acres. Seventy acres already met the definition of a restored reef due to older existing restoration projects (22 acres) and historic reefs (48 acres). Nonprofit organizations finished the remaining restoration work in 2018. Beyond the planned restoration work, in 2020, partners installed 405 oyster castles—instant habitats made of concrete, shell and limestone—and then seeded them with spat-on-shell.
- The Lynnhaven River restoration plan calls for 152 acres of restored reefs. Of this total, 89 acres already met the definition of a restored reef by virtue of the existing natural oyster population. By the end of 2021, partners had restored 25 acres of reef. In 2022, 13 acres of reefs were constructed. Due to issues with the construction material and reef locations, these reefs are now under consideration for mitigation efforts in 2023, including possible removal.
- The Piankatank River’s restoration work was completed in 2021 with 444 acres of restored reefs, exceeding the restoration plan’s goal of 440 acres of restored reefs. Of this total, 203 acres already met the definition of a restored reef while partners built an additional 241 acres of reefs.
- The lower York River restoration plan calls for 200 acres of reefs to be restored. Of this total, two acres already met the definition of a restored reef. Partners built an additional 193 acres, bringing the total to 195 restored acres. Partners are focusing much of their oyster reef construction work in the lower York River in 2023.
- The Great Wicomico River restoration work was completed in 2021 with 124 acres of restored reefs, exceeding the restoration plan’s goal of 122 acres of restored reefs. Prior to the outcome, partners had restored 100 acres of existing reefs. In 2021, partners worked collaboratively to restore the remaining 24 acres.
In 2019, Virginia selected a “bonus” tributary for restoration, the Eastern Branch of the Elizabeth River. In 2020, partners constructed 21 acres of reefs in the Eastern Branch, which, when added to previously restored acres, totals about 24 acres of oyster reefs in this tributary. The Elizabeth River’s Eastern Branch oyster population is considered fully restored. Monitoring will take place at three and six years after construction to assess whether the restored reefs meet the success criteria established in the Oyster Metrics.
Overharvesting, disease and habitat loss led to a severe drop in oyster populations over the last century. Oyster restoration at the tributary level aims to increase oyster populations to provide the ecosystem services that oyster reefs perform. Oyster reefs promote clean water and provide food and habitat. In certain situations, they can protect shorelines from some wave erosion. For these reasons, oyster reefs may help communities prepare for some of the disruptions that climate change can cause.
Tracking our progress toward restoring oyster reefs is critical to understanding our progress toward enhancing climate resiliency.
To achieve this outcome, Chesapeake Bay Program partners have committed to:
- Planning and implementing oyster reef restoration in select Maryland and Virginia tributaries.
- Coordinating and communicating our progress toward, and research related to, oyster reef restoration.
Monitoring and assessing progress toward the outcome will occur at the reef, tributary and Chesapeake Bay-wide levels. Reef- and tributary-level monitoring will take place at three and six years after restoration is complete to determine if a tributary has been successfully restored according to agreed-upon metrics.
As part of the Chesapeake Bay Program’s partnership-wide implementation of adaptive management, progress toward this outcome was reviewed and discussed by the Management Board in November of 2021. It will be reviewed and discussed by the Management Board again in November 2023.
Logic & Action Plan
Chesapeake Bay Program partners have committed to taking a series of specific actions that will support the management approaches listed above.
- Completed initial in-water restoration of the St. Mary's River.
- Completed initial in-water restoration of the Great Wicomico, Piankatank, and Tred Avon rivers.
- Published NOAA Technical Memorandum on research into ecosystem services provided by restored oyster reefs.
The Sustainable Fisheries Goal Implementation Team leads the effort to achieve this outcome. It works in partnership with the Vital Habitats, Water Quality and Healthy Watersheds goal implementation teams.
Participating partners include:
- Maryland Department of Natural Resources (State of Maryland)
- Virginia Marine Resources Commission (Commonwealth of Virginia)
- City of Norfolk
- City of Virginia Beach
- Christopher Newport University
- Virginia Commonwealth University
- Virginia Institute of Marine Science
- University of Maryland Center for Environmental Science
- Potomac River Fisheries Commission
- Chesapeake Bay Commission
- National Marine Fisheries Service (National Oceanic and Atmospheric Administration)
- U.S. Army Corps of Engineers
- U.S. Fish and Wildlife Service
- Chesapeake Bay Foundation
- Elizabeth River Project
- Lynnhaven River NOW
- The Nature Conservancy
- Oyster Recovery Partnership
- Oyster Reefkeepers
- Pleasure House Oysters