Virginia Institute of Marine Science
Restoration of Eelgrass and Bay Scallops to Virginia’s Seaside Bays
Project Description as Proposed:
The Seaside Bays of Virginia’s Eastern Shore are renowned for their local, regional, and global value to migratory birds and marine life of all kinds. The bays serve as critical nursery areas for numerous finfish, both predator and prey, and essential habitat for shellfish, coastal sharks and sea turtles. This inlet-influenced, ocean dominated system has very good overall water quality. But the seaside bays suffered two ecosystem state changes in the last century: the loss of the seagrass Zostera in the 1930’s due to a wasting disease and concurrent hurricanes (Orth et al. 2006) and the more recent commercial extinction of the native oyster in the 1990’s due to over-harvest and disease. The state change in native oyster populations resulted in the loss of critical ecosystem services such as water filtration, habitat, and biomass provided by the oysters. The state change in seagrass likewise resulted in the loss of critical ecosystem services and the provision of food and nursery habitat for numerous avian and marine species, most especially the bay scallop, Argopecten irradians.
The bay scallop, Argopecten irradians, once supported a valuable fishery in the seaside bays of Virginia’s Eastern Shore. Landings from this fishery peaked in 1929 at 8.3 metric tons, declining to 3.0 metric tons in 1932 before collapsing to zero in 1933 (Orth et al. 2006). The decline between 1929 and 1932 is presumed to be a response to a western Atlantic pandemic decline in eelgrass, Zostera marina, which provides critical habitat for juvenile bay scallops. The most significant hurricane to impact the region during the 20th Century struck in August 1933 burying the eelgrass beds and eliminating the bay scallop population throughout the region. No evidence of a breeding population has been observed within the region for the past 77 years.
From 2003 to 2008, an innovative and highly successful public-private restoration partnership created by the Virginia Coastal Zone Management Program, called the Seaside Heritage Program (SHP) used NOAA/CZM funds to restore coastal resources and enhance ecotourism in and around the seaside bays. In addition, several of the SHP partners, including the Virginia Marine Resources Commission (VMRC), the Virginia Institute of Marine Sciences (VIMS), and The Nature Conservancy (TNC) also received NOAA-TNC Community Restoration Program funds and other sources of private funds over this 6 year period to supplement and build on the earlier successes of the Seaside Heritage Program. VIMS also received financial support for seagrass restoration from the Army Corps of Engineers and the Virginia Department of Transportation. In addition, the VMRC-VIMS-TNC restoration partnership was successful in competing for a NOAA ARRA project that was aimed at restoring seagrass, oyster and bay scallops between 2008 and 2011.
Over the past decade remarkable success has been achieved in restoring eelgrass to the southern seaside bays (Orth et al. 2006, 2010). While this restoration effort is still underway, newly-formed beds are spreading rapidly and all indications suggest that a robust population of eelgrass will spread throughout much of its previous extent within these bays. The return of this important nursery habitat opens the possibility of restoring bay scallops to the region. VIMS initiated this effort in 2009 with support from the Campbell Foundation for the Environment and NOAA Restoration Center. To date VIMS has had excellent results in spawning scallops in both the spring and fall. A land-based nursery has been constructed for rearing the very early post-set animals and a field-based nursery for rearing scallops through the juvenile stage. Approximately 60,000 scallops have been deployed in cages within the grass bed in South Bay to serve as spawning stock; another 15,000 have been free-planted within the grass bed. The expectation is that successful restoration of a viable bay scallop population to this region will require up to 10 years of sustained effort—a remarkably short time given the long period of local extinction, but it is comparable to the successful timeframe in restoring eelgrass beds to the region.
Numerous examples of bay scallop restoration appear in the scientific and resource management literature. However, it appears none have faced the challenge of restoring a viable population to a region where it had been completely extirpated for over three-quarters of a century. Such an effort will require addressing difficult issues related to broodstock selection, management to avoid co-introduction of other species, the development and maintenance of local broodstocks and the reconstruction of a regional metapopulation.
This project will support ongoing eelgrass and bay scallop restoration work in 2011 and 2012. The eelgrass restoration component will follow a series of distinct tasks that have proven to be successful during the last eight years of seagrass restoration, including the monitoring of plant performance and the environmental conditions in the transplanted beds. These tasks encompass: 1. Collection of seeds, 2. Processing and storage of seed material; 3. Distribution of seeds; 4. Monitoring of plant success; and 5. Monitoring of water quality in the restored areas.
The scallop restoration component will continue a restoration approach developed over the last 2 years which is also proving successful. Specific tasks include: 1. Spawn adult scallops from newly-developed Virginia stocks (produced from animals formerly collected in North Carolina); 2. Rear several million larvae through the hatchery phase; 3. Transfer 100’s of thousands of scallops to a nursery facility to grow through the juvenile stage; 4. Plant 10’s of thousands of adult scallops in the seagrass beds; 5. Monitor for the presence of newly recruited scallops to the seagrass beds; and 6. Maintain broodstocks for the next year’s spawn.
Orth, R. J., M. L. Luckenbach, S. R. Marion, K. A. Moore and D. J. Wilcox. 2006. Seagrass recovery in the Delmarva Coastal Bays, USA. Aquatic Botany 84:26-36.
Orth, R. J., S. R. Marion, K. A. Moore, and D. J. Wilcox. 2010. Eelgrass (Zostera marina L.) in the Chesapeake Bay Region of Mid-Atlantic Coast of the USA: Challenges in Conservation and Restoration. Estuaries and Coasts 33:139-150.
Robert J. Orth (SAV), 804.684.7392 (Orth); firstname.lastname@example.org
Mark Luckenbach (scallops), 757.787.5834 (Luckenbach); email@example.com
10/1/2009 - 9/30/2010; Project Completed
Final Product Received:
Eelgrass and Bay Scallop Restoration in the Seaside Bays of Virginia Final Report (pdf)
Project Summary Provided by Grantee:
Objectives of funding provided by the Virginia Coastal Zone Management Program’s FY 2009 funds were to: 1. Plant eelgrass using seeds to increase the recovery of the eelgrass beds into the Virginia coastal bays region; 2. Determine seedling establishment rates and evaluate the effectiveness of the seed planting; 3. Monitor water quality conditions to assess changes that may be associated with the eelgrass recovery and to identify new potential areas for restoration activities; 4. Assess eelgrass bed growth and expansion; and 5. Continue bay scallop restoration efforts initiated in 2009 with NOAA’s American Reinvestment and Recovery Act Funds
In 2011, 3.1 million seeds were broadcast into Cobb and Spider Crab bays. Cobb Bay received 1. 1 million seeds into 2.4 ha, while Spider Crab Bay received 2.0 million seeds in 5.7 ha. Seed dispersal from plants in the restored plots to nearby unvegetated areas has resulted in an estimated 1,769.12 hectares (4369.72 acres) containing eelgrass by 2011 in these four bays, almost 14 times the originally seeded area.
The results of water quality assessment made here through 2011 indicate that this trend is continuing in South Bay. With the establishment of a new intensive monitoring station in Spider Crab Bay, measurements demonstrate that water quality at Spider Crab Bay is currently characterized by higher turbidities and phytoplankton levels than South Bay where the eelgrass beds are better developed.
Our scallop restoration approach to date has involved three basic steps: (1) spawn scallops in the spring, (2) rear them as rapidly as possible in land-based and field-based nurseries to approximately 20 mm in size, and (3) deploy them in cages at high density in the grass bed to serve as field spawning stock. The preliminary assessment of wild scallop populations in the grass bed in the fall of 2011 and more thorough assessment in the summer of 2012 clearly indicate that this approach is being successful in establishing a wild population.
Disclaimer: This project summary provides the federal dollars initially awarded to the grantee. Due to underexpenditure or reprogramming of grant funds, this figure may change. For more information on the allocation of coastal grant funds, please contact Laura McKay, Virginia Coastal Program Manager, at 804.698.4323 or email: Laura.McKay@deq.virginia.gov
A more detailed Scope of Work for this project is available. Please direct your request for a copy to Virginia.Witmer@deq.virginia.gov