Restoring oyster reefs
Tue, Jul 20 2010 at 12:17 PM
By The Nature Conservancy
In April 2010, The Nature Conservancy, working with partners, began restoring 3.4 miles of oyster reef off the coast of Louisiana that border some 350 acres of marshland. Funding for the project is being provided by the American Recovery and Reinvestment Act through the National Oceanic and Atmospheric Administration (NOAA). The restoration sites are at Grand Isle St. and Bernard Marsh. (Download maps at right.)
Oyster reefs provide valuable benefits to wildlife and people.
- Because oysters filter water when feeding, they help improve water quality and clarity – a single oyster can filter up to 50 gallons of water each day!
- Oyster reefs can protect coasts and marshes from erosion and storm surges.
- Oyster reefs provide valuable wildlife habitat for species like fish, shrimp and crabs -- more than 170 marine species have been documented at reefs in the northern Gulf of Mexico.
- Seventy percent of the nation’s total landings of oysters come from the Gulf of Mexico.
- Oysters, their reefs and the increased habitat they provide for commercial and sport species help fuel the local commercial and sport-fishing industries.
Overfishing, dredging, habitat loss and the deterioration of water quality have decimated much of the Gulf’s oyster reefs. A recent global study revealed an 85 percent decline of native oyster reef habitat worldwide. But there is good news – the same study pinpointed the northern Gulf of Mexico as one of the most viable places for oyster reef restoration.
To build the oyster reefs at Grand Isle and St. Bernard Marsh, the Conservancy contracted with Coastal Environments, Inc., to construct interlocking triangular structures made of welded steel with space for mesh bags of oyster shells – a technique proven to be highly successful at the Conservancy's Mad Island Marsh Preserve in Texas. Once in place, these artificial reefs come alive as oyster larvae attach to the structures and grow.
The project is also boosting the local economy by creating or maintaining 57 jobs – particularly important in these areas hit hard by hurricanes Katrina and Ike. NOAA provided over $4 million in Recovery Act funding to the Conservancy for these projects as well as funding for seven other coastal restoration projects across the nation.
Louisiana’s coastal marshes provide essential habitat for numerous fish, birds, and marine mammals. Approximately 75 percent of the nation's commercial fish and shellfish, and 80 to 90 percent of fish caught for recreation depend on estuaries at some stage in their life cycle.
Creating and protecting habitat for marine species benefits people, too.
- The 2008 dockside value of commercial landings of Louisiana’s oysters alone was $38.8 million. Shrimp and crab landings totaled greater than $64 million and $210 million respectively.
- Recreational fisheries also contribute substantially to Louisiana's economy, generating almost $49.9 million dollars in state and local sales tax revenue in 2006. During that same year, anglers spent more than $472 million on saltwater recreational fishing in Louisiana. This activity supported 7,733 jobs with nearly $229 million in earnings.
- Louisiana is second only to Alaska in commercial fisheries landings.
- One of out every 70 jobs in Louisiana can be attributed to commercial fisheries.
While salt marshes are among the most productive habitats in the world, in Louisiana they are changing forever. Because of complex problems such as shoreline erosion, between 25 and 35 square miles of Louisiana’s coast are lost each year, representing 80 percent of the total coastal wetland loss in the entire continental United States. The ecological and economic repercussions of this land loss are profound.
Coastal marshes are valuable for their role in storm protection, shoreline stabilization, flood attenuation, and hurricane protection to the Louisiana coast, protecting billions of dollars of infrastructure and the lives of those who live along the coast. With the devastation of hurricanes Katrina and Rita, scientists, managers, policy makers and the public witnessed the direct link between coastal habitats, fishing and Louisiana’s economy. Nearly $168 million in seafood revenues and an estimated 3,400 fishing fleets were lost.
Oyster reefs act as natural coastal buffers by absorbing wave energy, reducing erosion and trapping suspended sediment. The shorelines that will be protected border approximately 350 acres of existing marsh and this treatment will potentially facilitate the creation of an additional 35 acres of emergent marsh.
Louisiana State University has developed a scientific plan to monitor both the short- and long-term success of this project as measured by reef establishment, shoreline changes and improved habitat for other marine species.
MNN is working with The Nature Conservancy to bring you state-by-state environmental information.