"The world's tallest building stands in Dubai. The largest city is in Japan. Brazil's Amazon is the largest rain forest. And the largest airport sits in the middle of a Saudi Arabian desert. But Maryland can lay claim to the world's largest man-made oyster reef." That's how the Washington Post referred to a vast, multi-partner effort, of which we were a part, to restore the oysters in Maryland's Harris Creek.
Over the last four years, a partnership of agencies and groups led by the Maryland Department of Natural Resources and the National Oceanic and Atmospheric Administration planted an estimated two billion oysters on 350 acres of river bottom on Harris Creek on the Eastern Shore.
The ultimate goal is a thriving network of reefs in Harris Creek where oysters have achieved a critical mass and reproduce without the help from man. After six years, if the oysters survive well and mature, the partners hope to declare Harris Creek as the first tributary of the Chesapeake Bay restored to self-sufficiency.
The work started in Harris Creek in 2011. At the time, there was perhaps only one to three acres of healthy oyster reef remaining in the creek that once boasted 1,500 acres. The bottom had too much mud to support historic quantities of oysters.
When oysters reproduce, the larvae need a hard substrate upon which to attach. Normally, they attach to existing oysters and shells. So, the first step in restoring the creek was to put down man-made beds of oyster shells and stone. Then, the partners started "planting" hundreds of millions of "spat" (or baby oysters) the size of a dime attached to old oyster shells. The U.S. Army Corps of Engineers and DNR conducted most of this work.
Then, other partners, led by the University of Maryland's Horn Point Laboratory and Oyster Recovery Partnership, planted hundreds of millions of "spat" (or baby oysters) attached to old oyster shells on the prepared beds.
With the restoration effort, oysters in Harris Creek are now at densities they were 50 to 100 years ago. If you could snorkel over the reef, you'd see knots of growing oysters clustered together over hundreds of yards—a sort of massive, jagged, shag carpet.
Achieving the impressive planting numbers and acres is a milestone for which we all should be proud. But it's just the beginning. Ultimately, the plan is to restore large oyster reefs in 10 tributaries of the Chesapeake over the next 10 years. Two other projects in Maryland and three in Virginia. And that's great news for the health of the Chesapeake as each adult oyster can filter and clean up to 50 gallons of water per day—gobbling up algae, and removing dirt and nitrogen pollution.
By 2025, the 10 super reefs should serve as oyster spawning dynamos that create rich habitat for fish, and filter billions of gallons of water in each tributary. To function properly, the reefs will need to grow vertically. Historic reefs in the Bay were more like jagged skyscrapers, but harvesting knocked them down. Right now, the Harris Creek reef is starting out relatively flat but will grow over time. While the reefs will be off-limits to harvesting, scientists believe they likely will help boost the population of oysters in general, including those in nearby harvesting areas.
As CBF's Maryland Eastern Shore Director Alan Girard told the Post: "The Harris Creek sanctuary will serve as a reproductive engine, with the potential to repopulate wide areas outside the creek . . . [it is] a significant step in Maryland's plan to restore what was once a vast underwater food factory and water filtering system. Everyone will benefit from that restoration."