Louisiana Tries New Recipe for Saving Its Oysters

Louisiana once produced half of the nation’s wild oysters, but shellfish populations have declined in recent years. Now the state has a new plan to boost the mollusks’ reproduction, restore its decimated oyster population, and eventually return to bountiful harvests.

Officials in the Bayou state began developing the recovery plan in 2019 after a study that year revealed the lowest population size in public oyster areas ever recorded—a decline driven by extreme weather, major flooding, over-harvesting, the 2010 Deepwater Horizon oil spill, changes in water salinity, and increasing ocean temperatures. Governor John Bel Edwards (D) and the Louisiana Legislature pushed for the plan, which was completed in December.

The $132 million, five-year plan lists several goals to increase the oyster population:

• Create and protect at least 40 acres of oyster spawning reefs where harvest is prohibited. No-take spawning reefs give oysters a chance to grow larger and older so they can produce more larvae. These larvae can travel beyond the protected reefs to help boost oyster populations over a wider area. And as the spawning reefs mature, they create additional habitat for other economically important species such as blue crab, spotted seatrout, and red drum.
• Improve at least 1,000 acres of existing oyster reefs by adding shells, the main building block of reefs. Baby oysters use shells as a place to attach themselves and grow. When too many oysters are removed from the water, there isn’t enough shell to support future generations. Adding shells or shell-like materials such as crushed limestone can help make up for the loss.
• Develop an oyster variety that tolerates low salinity. The mollusks don’t survive when too much freshwater enters their normally salty ocean areas, which has happened more frequently when storms and floods push freshwater onto reefs. During the past few years, Mississippi River overflows have brought unprecedented and vast amounts of freshwater into oyster grounds in Louisiana and Mississippi, driving many harvesters out of business.
• Expand monitoring by installing devices along the coast to collect information about salinity, temperature, pH, and oxygen levels.
• Provide government help to the industry by contributing materials to build new reefs, and by expanding operations at a state-owned hatchery where larvae grown on shells are later planted on reefs to restore and maintain healthy oyster populations.
• Expand oyster aquaculture acreage and increase the number of permits. Oyster farmers can use larvae to grow the shellfish in tanks on land or in racks, bags, and cages suspended above the seafloor.

Healthy reefs not only deliver more oysters for people to eat but also convey environmental benefits. Oysters filter pollutants from the water, and reefs absorb wave energy, stabilize shorelines, and provide habitat for many marine animals, including commercially and recreationally valuable fish species. Louisiana’s oyster recovery plan, if it’s fully implemented, will benefit the economy, fishermen, and coastal communities, along with the marine ecosystem.

Holly Binns directs The Pew Charitable Trusts’ conserving marine life program in the Gulf of Mexico and U.S. Caribbean.