Oysters are a beloved seafood dish across the country, especially along the gulf and east coast. Most frequently served raw on the half shell, oysters must be shucked before serving, which means the shell has to be pried open to get to the tasty part on the inside. Preparing and consuming oysters results in a lot of shells to dispose of. Rather than throwing them in the trash, many restaurants have taken to recycling this byproduct. Shells can be observed to be used in lieu of gravel or mulch around coastal parking lots and buildings. However, recently, scientists have been using these shucked shells to improve the conditions of coastal estuaries!
Estuaries are the areas where rivers flow into the ocean. They are very productive and diverse ecosystems that act as breeding grounds for numerous species. There are many different habitats that can be found within the estuary, the most important of which is the oyster reef. Generations of oysters, growing one on top of the other, produce reefs that are crucial to the vitality of the estuarine system.
Oysters provide a variety of different services and are a keystone species of estuaries, meaning that without them, the stability of the entire ecosystem is at risk. First, the oyster reefs act as wave breaks slowing down the water off the ocean and mitigating erosion at the shoreline. Second, the reefs provide excellent habitat for fish and invertebrates. Finally, the individual oysters are filter feeders. They feed on phytoplankton and can also filter out pollutants leading to improved water quality. Unfortunately, we humans found one more great quality in oysters: food. Overharvesting of the oysters in the estuaries of Georgia in the 1930s led to significantly decreased populations. This means all the positive impacts they have on the estuarine systems have been significantly reduced.
Since 2004, efforts have been made to reestablish oyster reefs throughout coastal Georgia. The tricky part is that oysters need a hard surface on which to grow on. Without the scaffolding of previous generations, there really is not much hard substrate to be found in estuaries. Scientists and conservationists have had to build the base for the new generations. They do this through collaboration with restaurants and recycling the shells of the oysters that we eat. Once cleaned, these shells are loaded into wire cages and sunk into the waters to form the foundation for new reefs. With an established “reef” juvenile oysters can attach and begin to repopulate and provide all the benefits that had previously been missing.
Efforts to reestablish reefs are not exclusive to Georgia. All along the gulf and as far up as they are native on the east coast, initiatives are underway to revitalize estuarine systems by bringing the oysters back. In New York Harbor, the Billion Oyster Project has been underway since 2008 with the goal of establishing 1 billion oysters. No one can complain about improved water quality and shoreline stabilization, and established populations can provide some locally sourced eats too!
Learn more:
https://gacoast.uga.edu/outreach/programs/oyster-reefs-georgia/
https://www.npr.org/sections/thesalt/2018/10/10/654781446/oysters-on-the-half-shell-are-actually-saving-new-yorks-eroding-harbor
