Building oyster reefs for wildlife and people
Long before the explosion of the Deepwater Horizon oil rig and ensuing spill, The Nature Conservancy was at work to improve the health of the Gulf of Mexico and its marshlands. Fishing practices, dredging, habitat loss the deterioration of water quality, and storms have reduced the quality and extent of much of the Gulf’s oyster reef habitat. The Gulf Coast of Louisiana is one of the most viable places for oyster reef restoration.
TNC has constructed six miles of oyster reef in Louisiana: at Vermilion Bay, Grand Isle, along the St. Bernard Parish marshes, and in Calcasieu Lake. Each reef uses a slightly different structure to recreate an oyster reef and its functions. Sometimes they are built with concrete rings, sometimes with large baskets full of recycled oyster shells and other material.
The chapter's latest mile of reef, completed in Calcasieu Lake in 2017, is a mile of gabion baskets filled with limestone and shells. Placed near the shore to mimic natural oyster reefs, this project is adjacent to the Sabine National Wildlife Refuge and within a protected public harvest area. TNC reefs are not open to harvest so that they can recover habitat and provide oyster seed.
Oyster reefs provide valuable benefits
- 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 natural oyster reefs in the northern 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.
Both A Habitat and A Fishery
Louisiana’s coastal marshes provide essential habitat for numerous fish, birds, shellfish 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. Both recreational and commercial fisheries are critical to the Louisiana economy. Louisiana is second only to Alaska in commercial fisheries landings, and one out of every 70 jobs in Louisiana can be attributed to commercial fisheries.
"Oysters have been managed as a fishery," says Coastal Program Director Seth Blitch, "but they need to be managed as a habitat, too. It needs to be both—these are mutually inclusive pursuits." Further collaboration efforts are taking shape at Calcasieu Lake, where The Nature Conservancy is developing a coalition to manage oyster resources.
This collaborative approach was signaled by recent legislation in Louisiana. The Sabine Lake Reef, a public reef that has not been open to harvest since 1966 because of water quality issues, received permanent protection in 2018, when the Governor signed into law a bill that had passed through the legislature unanimously. This ruling is consistent with growing sentiment in Louisiana that oyster habitat is valuable for more than just its fisheries.
Natural Solutions to a Critical Problem
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, roughly 16 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.
Because they buffer storm energy and stabilize shorelines, coastal marshes protect billions of dollars of infrastructure and the livelihoods of those who live along the coast. With the devastation of recent hurricanes, scientists, managers, policy makers and the public have witnessed the direct link between coastal habitats, fishing and Louisiana’s economy.
The Nature Conservancy is using oyster reef restoration as a direct approach toward slowing coastal erosion, as a demonstration of the importance of these habitats, and as a venue to develop collaborative approaches to managing oyster reefs as both a fishery and a habitat.