Most people only think about oysters if they’re at a seafood restaurant, but these local bivalve animals are so much more than a meal. Oysters, scientists have proven, are critical to creating healthy water quality and thriving habitats in estuaries like the Chesapeake Bay. Yet, disease, pollution and over-harvesting have greatly reduced the eastern oyster population in local waterways.
In an effort to save the Chesapeake Bay and its ecosystem, local agencies are partnering with community members to facilitate oyster restoration projects and in-depth studies. Whether or not they are on the menu, the importance of oysters to the natural environment is worth understanding.
Why Oyster Restoration Matters
There are several reasons why agencies have focused on restoring oysters, and some of them are outlined below.
Oysters Filter Water
As the largest estuary in the United States, the Chesapeake Bay has struggled with dramatic increases in polluted rainwater runoff that comes from its massive watershed spanning six states. As the population of the region soars above 13 million people, everything from pesticides on front lawns to large agricultural fields have impacted the Bay.
Nutrients like nitrogen and phosphorus, once absorbed naturally by wetlands and forests, now flow straight into the waters. This pollution impacts the grassy bottom of the estuary, which in turn makes it easier for the sediment on the bottom to churn up. Fish, reptiles and mammals looking for habitat go elsewhere – or die – when waters get too murky.
Oysters purify water because they are what is known as filter feeders. Oysters filter water by sucking in the liquid over their gills to eat the microscopic plankton floating nearby. The other particles they suck in, such as nitrogen and suspended sediment, are either digested or combined into heavier bits that sink out of the water column to the bottom. The water becomes clearer and more hospitable in the process.
At one point, the oyster population of the Chesapeake Bay was able to filter more than 19 trillion gallons in a week, the equivalent to the volume of water in the entire Bay. But today, with the increased pollution and the diminished oyster population, it would take more than a year to filter the Bay.
Oyster Reefs Provide Habitat
Oyster reefs grow in clusters, with new juveniles growing on top of existing shells. The importance of oyster reefs is massive: The structure can be up to 50 times the habitat area of a similarly sized mud bottom. This provides small, safe spaces to feed and grow for everything from sea squirts and sponges to crabs and juvenile fish.
Unfortunately, the Bay’s oyster population is now estimated to be as little as 1% of its original size due not only to pollution, but also over-harvesting and disease. It is believed that at least 80% of the Bay’s oysters in any given year don’t reach the age of 3 due to these diseases.
Another problem facing oysters in the Chesapeake Bay is habitat loss caused by the overwhelming amount of pollution. Not only are the Bay’s oysters unable to filter it all, but there are “dead zones” of low oxygen that make it nearly impossible for oyster larvae to mature. Not surprisingly, the strain makes these bivalves that much more likely to become diseased.
Oyster Restoration Efforts Underway
To address these complex issues, scientists, governmental agencies and nonprofit volunteers have partnered in a variety of projects. First, both Maryland and Virginia have commissions that oversee the annual oyster harvest to encourage sustainable practices that won’t decimate the overall population.
The Chesapeake Bay Foundation underscored the importance of oysters by creating oyster restoration centers in both Maryland and Virginia. There are many oyster restoration projects underway through these centers. Scientists have tanks that allow them to produce spat, or juvenile oysters, which they then allow to attach on old oyster shells. Each year, volunteers help to transplant millions of spat on to protected reefs in the Bay. These researchers are also studying the potential of breeding strands of oysters that are genetically more resistant to the diseases impacting the current population.
Plus, the National Oceanic and Atmospheric Administration is working on detailed surveys of the oyster population using acoustic seabed monitoring. This surveying helps scientists understand the state of the oyster population while also discovering new locations that are suitable for protected beds for juveniles. These replanting areas in the Chesapeake Bay need to have a sandy or shelly bottom and uniform depth. Once these reefs are created, divers continually monitor the success of the project.
Because shells are becoming increasingly difficult to procure, scientists have also been researching different kinds of substrates that can be used to grow oysters both in the laboratory and in the Bay itself. They experiment with concrete, construction debris, coal ash and old bits of porcelain to see what can work without causing any harm the environment. Parts of the old Chesapeake Bay Bridge were even sunk to create an oyster sanctuary in the Severn River.
What Can Communities Do to Help?
While scientists remain busy, current citizen-focused work also highlights the importance of oyster reefs. The Chesapeake Bay Foundation reported citizen scientists and students are using local docks to plant oyster gardens. In these gardens, a few cages out of wire mesh hang from the dock. The gardeners then “plant” the seed oysters on old shells and care for the cages for about a year, or until the oysters are at least an inch long. Then, the oysters are returned to the oyster restoration centers for the staff scientists to add to the protected reefs in special areas of the Chesapeake Bay.
Those who are naturally interested in protecting and enhancing the health of the Chesapeake Bay can also help be a part of the Shell Recycling Alliance. Shell recovery is a program designed to reclaim shells used to rebuild natural oyster habitat. While you may not think about it after you are finished enjoying some oysters over lunch, those shells can be recycled by restaurants instead of dumped in the landfill.
Each year, the Oyster Recovery Partnership collects 33,000 bushels of shells from almost 350 restaurants and 70 drop-off sites for the public throughout the Bay region. Not only does this help the health of the local waters, it also saves landfill space and the cost seafood businesses would otherwise pay in waste collection fees. Since the Shell Recycling Alliance began in 2010, the group has collected enough shells to help plant 950 million oysters back in the Chesapeake Bay.
Residents in the watershed of the Chesapeake Bay should take additional steps to reduce the toxins that come from their property. This includes properly disposing of hazardous waste like oils and anti-freeze, eliminating herbicides and pesticides from the lawn, maintaining septic systems and landscaping with native plants.
Finally, addressing pollution remains part of the long-term solution. Those interested in protecting the ecosystem of the Chesapeake Bay and other at-risk environmental areas should consider pursuing a college degree which relates to these concerns.
- Online Bachelor of Arts in Sustainability Management: A multidisciplinary education that combines core business subjects with an emphasis on sustainable practices. The program draws on topics from subject areas including economics, management, policy analysis and more.
- Online Bachelor of Arts in Environmental Studies: Provides a broad foundation of knowledge in key areas like science, economics and how humans fit into the natural world. By studying topics that emphasize the interdisciplinary nature of the field, you will be able to apply what you learn in the workplace.
Virginia Wesleyan Online’s program emphasizes real-world skill development along with flexibility, so you can complete your education in a format that works for you. Our classes are taught by expert instructors with years of experience in their fields. Whether you choose to pursue corporate sustainability, environmental consulting or another discipline, our environmental programs prepare you for a career that makes a difference.