N.C. Oyster Hatchery Program<\/a> and others. All totaled, groups have constructed more than 150 acres of oyster reef. Currently, nine existing oyster sanctuaries are in place in estuarine waters from Dare to Carteret counties, with two more in the planning stages.<\/p>\nSanctuaries are built on previously viable oyster producing sites by using a combination of natural oyster shell and\/or Class B rip-rap marl. These reefs attract native oyster larvae, as well as clams, juvenile finfish, crabs and marine organisms, which in turn attract larger fish, enhancing hook-and-line fishing.<\/p>\n
Harvest of oysters and the use of bottom-disturbing gear are prohibited in the sanctuaries, allowing broodstock oysters to develop.<\/p>\n
Each oyster produces millions of eggs annually that are carried by currents and tides to surrounding areas. By developing and protecting a broodstock, the availability of robust native oysters in adjacent waters increases.<\/p>\n
For the first three weeks of an oyster’s life, it is a free-swimming animal that is carried about by currents. After the third week, the oyster moves to the bottom and attaches itself to a clean, hard surface to survive.<\/p>\n
During the summer months, DMF plants shell and rock, known as cultch, to provide additional habitat for larval oysters. Large vessels transport the cultch out to a designated site. The shells are either dumped off with a front-end loader or sprayed off with a high power hose. More than 500,000 bushels of cultch are planted annually in the state.<\/p>\n
OYSTER RECYCLING<\/h2>\n
To create sizeable reefs, North Carolina is pooling its resources. In 2003, the state launched an innovative recycling program to collect oyster shells from individuals and businesses and place them back in the water.<\/p>\n
A mound of oyster shells placed in brackish or marine water with good tidal flow will quickly become colonized by a multitude of marine organisms. This mound or reef helps to produce oysters.<\/p>\n
Researcher Troy Alphin and UNCW graduate student Ted Wilgis sort through a mound of oysters.<\/p><\/div>\n
“Oyster conservation is important because of benefits on multiple fronts to commercial fishermen, shucking houses and the seafood industry, as well as environmental factors \u2014 water filtration and habitat creation,” says Marc Turano, North Carolina Sea Grant mariculture and blue crab specialist. “Efforts to understand reef function can ultimately ‘shape’ how and where we construct reefs during restoration efforts.”<\/p>\n
To improve future oyster sanctuaries, the South Carolina Sea Grant Consortium, Coastal Carolina University, The Nature Conservancy and the S.C. Department of Natural Resources sponsored a regional Oyster Restoration Workgroup in 2004. Participants identified key monitoring metrics that should be included in restoration projects.<\/p>\n
The meeting resulted in several studies, including the North Carolina Sea Grant project.<\/p>\n
“Aside from the establishment of a healthy population of oysters, consensus on what constitutes a successful reef restoration project currently does not exist,” Posey says.<\/p>\n
Their results will be compared to other projects adopting the same metrics and sampling protocols, allowing regional comparison of reef function and methodological success.<\/p>\n
Researchers also will be looking at the differences between reefs that were established through simple shell placement and adjacent reefs established with shells seeded with live oysters.<\/p>\n
“Seeding is a labor-intensive approach, whose cost-effectiveness has not been well tested,” Posey says.<\/p>\n
The scientists are measuring the shell height of each oyster, as well as the thickness of the shell layer. “An insufficient underlying bed may allow the restored reef to sink before live oysters have been established enough to keep up with sedimentation and burial,” Posey says. “And too much shell base may raise the substrate and put the reef heights in intertidal beds beyond optimum levels.”<\/p>\n
UNCW graduate students Sharon Tatem and Wilgis often survey and assess fish, shrimp and crabs using the reefs.<\/p><\/div>\n
Because of the scarcity of shell for restoration projects, there is a desire to place the minimum amount of shell in areas that will allow a high likelihood of success, Posey explains.<\/p>\n
“Few studies have examined variation in the success of intertidal reefs built with varying shell bed depth,” he adds. “Enclosures of reefs within a marsh or channel area may promote larval retention and increase long-term recruitment success.”<\/p>\n
As part of the Sea Grant research, Wilgis is focusing on fish utilization of reef habitats by comparing nekton on artificial reefs to natural reefs. Nekton are animals that move freely in the water column.<\/p>\n
“By using traps, nets and visual observations, we are assessing the number of fish, shrimp and crab utilizing these reefs,” Wilgis says. ‘This is an important project because so much effort has been put into building reefs. We need to properly evaluate the projects and share the results with restoration practitioners, researchers, government agencies and shellfish growers and harvesters.”<\/p>\n
“The ultimate goal of these efforts is to increase oyster populations and habitats,” Alphin says.” We need to know what characteristics are most important for the long-term survival of oyster reefs in our coastal waters.”<\/p>\n
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VOLUNTEERS COLLECT OYSTER DATA<\/h2>\n
When researchers collect data on oyster larvae settlement throughout coastal North Carolina, the effort is labor intensive.<\/p>\n
To gather more data by hand, North Carolina Sea Grant researchers Martin Posey and Troy Alphin have recruited 66 volunteers along the North Carolina coast, from Brunswick to Hyde counties. Volunteers include concerned citizens, school groups and others, including the N.C. Aquarium at Pine Knoll Shores.<\/p>\n
Tatem and Wilgis help Alphin gather data from a created oyster reef at the edge of Masonboro Sound.<\/p><\/div>\n
The University of North Carolina Wilmington scientists provide racks and ceramic tile for volunteers to deploy off their docks to serve as surrogate oyster shells. Every few weeks the volunteers pull the tiles and measure the number of settled oysters, average temperature and salinity.<\/p>\n
“You have to own or have access to a dock to participate in the project,” Alphin explains.<\/p>\n
At the Pine Knoll Shores aquarium, the project will double as an educational tool to demonstrate spat collection to the public and raise awareness about the UNCW study, says Pat McNeese, research coordinator.<\/p>\n
By collecting year-round data on oyster settlement and density along the state’s coast, researchers will identify the time of year oyster spat, also known as larvae settle. The additional environmental data \u2014 including temperature salinity and rainfall \u2014 will allow scientists to compare oyster settlement to local conditions, and look for potential correlations.<\/p>\n