Aquatic Reefs

An aquatic reef, or oyster reef, is a solid, three-dimensional ecological community made up of densely packed oysters. Healthy reefs form when oyster larvae attach to larger oysters at the bottom of the Bay. Layers of oysters grow upward and outward, creating hard surfaces over the bottom that provide habitat for numerous aquatic species.

How are aquatic reefs an important habitat?

Aquatic reefs are more than just habitat—they are complex and diverse communities of fish and invertebrates.

• Oyster reefs are the largest source of hard surface on the Bay's bottom, which is mostly covered by soft sediment. Oyster larvae, as well as sponges, barnacles and many other invertebrates, must attach themselves to hard surfaces to survive and grow.
• With its many nooks and crannies, an aquatic reef can have 50 times the surface area of an equally sized flat mud bottom. Oyster spat find safety from predators, such as flatworms and mud crabs, among the reef's tiny crevices and empty shells.
• Fish such as gobies, blennies, toadfish and skilletfish all use aquatic reefs as their primary habitat.
• Many other aquatic species, including white perch, striped bass, blue crabs and diamondback terrapins, visit reefs to breed, find food or seek refuge from predators.

In what other ways are aquatic reefs important?

In addition to providing vital habitat, aquatic reefs play several other unique roles in the Bay.

• Reefs have high concentrations of oysters, which filter algae and pollutants from the water.
• Healthy aquatic reefs grow upward and outward, which protects oysters from lying on the Bay's soft bottom, where they are easily buried and suffocated by sediment.
• Oyster reefs attract some of the highest densities of fish of any type of habitat in the Bay, helping to support vibrant recreational fisheries.