First ever SAV map completed for region
The Albemarle-Pamlico National Estuary Program, or APNEP, recently announced the completion of a submerged aquatic vegetation map for the Albemarle-Pamlico region and the North Carolina coastline, the result of a multi-year partnership effort conducted by several state and federal agencies.
Submerged aquatic vegetation, or SAV, provides an important ecological habitat along the shorelines in North Carolina and Virginia. Many fish or shellfish in our estuary are dependent on this habitat during some phase of their life. As a result, this habitat directly supports recreational and commercial fisheries in North Carolina and along the East Coast. These industries contribute $1.75 billion dollars and 24,000 jobs annually to North Carolina’s economy.
Because of its importance to fisheries and overall aquatic health, environmental economists conservatively estimate that SAV habitats can be valued at $12,000 per acre per year, with some estimates being much higher. In total, 137,000 acres of SAV were mapped in the Albemarle-Pamlico estuary.
Fish, scallops and blue crabs rely on SAV in many ways. The vegetation can serve as a source of food, a place to hide from larger predators, or as nursery areas. SAV produces dissolved oxygen that helps prevent fish kills, and it also takes in excess nutrients that can harm estuarine waters. North Carolina’s Coastal Habitat Protection Plan and APNEP’s Comprehensive Conservation and Management Plan both detail strategies to monitor, protect and restore SAV.
Mapping SAV for such a large area is no simple task. Airplanes fitted with special cameras flew 1,795 miles along the estuarine coastline during a two-year period. Winds, waves, excessive humidity, or even sediment-laden water from recent rains could potentially interfere with the camera’s ability to detect SAV. To overcome these problems, volunteers along the coast sampled the water for clarity and communicated with project managers to clear the high altitude flights.
While the flights were occurring, boat crews directly surveyed SAV at locations under the flight lines. By taking this step, scientists were able to confirm that results obtained from the aerial imagery are fair depictions of the SAV that actually existed in the water.
“Committed citizens, dedicated professionals and strong agency partnerships were required to bring this challenging project to fruition,” said APNEP director Bill Crowell. “The success of this project bodes well for the future of ecosystem-based management in the Albemarle-Pamlico estuarine region.”
To complete the work, funding and technical expertise were provided by APNEP, N.C. Department of Environment and Natural Resources, N.C. Division of Marine Fisheries, N.C. Wildlife Resources Commission, U.S. Fish and Wildlife Service, and the National Oceanic and Atmospheric Administration. Some aspects of the project were contracted to private companies as well. Dewberry assisted with the collection of aerial imagery of the coastline, while Atkins provided expertise to develop the final maps.
With the completion of this map, officials have documented a majority of SAV throughout the Albemarle-Pamlico estuary and the North Carolina coast. Yet because SAV is sensitive to changes in temperature and water quality, its extent can change over time. For this reason, it is an excellent indicator of the health of the overall estuarine ecosystem.
In addition to its scientific applications, the new SAV map can be used to assist local, state and federal agencies, including the N.C. Division of Coastal Management, as they consider permit applications for water-dependent uses. While site visits will still be performed, the historical presence of SAV is one factor often considered in the permitting process.
Members of these agencies and other organizations continue their work of protecting and restoring habitats through the SAV Partnership. Among other projects, scientists with the partnership are now working to develop a monitoring program to track changes in this valuable resource, including a significant portion invisible in high-flight images. A variety of technologies can be used for SAV monitoring, including underwater cameras, boat-based sonar and aerial imagery. Now that the first map has been completed, scientists are considering the most efficient and cost-effective ways to combine these techniques to produce future versions of the map.
The map and GIS layers are available online at www.apnep.org.