|Oyster Restoration in Harris Creek|
Restorable bottom is hard bay floor in less than 20 feet of water that will support oysters.
Water Quality-Based on factors such as dissolved oxygen, temperature, salinity, nutrients, and water clarity. Oysters cannot survive if the water quality is very low.
Existing oyster reefs- Oyster reefs that were living in the area prior to our surveys. Many of these reefs are the result of substantial seed plantings by Maryland.
Restoration- To achieve restoration, each reef in the tributary should contain 50 oysters and 50 grams of dry weight/m2 over 30% of the reef, with at least two year classes (generations) surviving. One 3-inch oyster weighs about 1 gram. For the entire tributary to be restored, 50-100% of the restorable bottom must contain reefs that meet restoration requirements. The area must also cover 8-16% of the historic oyster footprint- area that oysters have historically inhabited.
Salinity - Amount of salt. Fresh water does not promote reproduction, while very salty water increases the risk of disease.
Spat-on-shell - Baby oysters growing on old oyster shells..
Circulation- The direction and strength of water flow. Oyster larvae will stay in the designated area to grow the population, and they also have the potential to settle in nearby tributaries, populating areas where oysters are harvested.
Projected placement, dispersal, and settlement:
Model created by Elizabeth North, USACE Baltimore District
In September 2010, the State of Maryland declared Harris Creek an oyster sanctuary from which oyster harvest is prohibited. It was selected for restoration based on its sanctuary status as well as its salinity, water quality, circulation, and existing oyster reefs. The restoration process on this tributary is a large-scale collaborative effort involving several state and federal agencies, and guided by the Harris Creek Oyster Restoration Tributary Plan, created by the Maryland Interagency Workgroup of the Sustainable Fisheries Goal Implementation Team.
To inform this Plan, extensive mapping efforts were made by the NOAA Chesapeake Bay Office and the Maryland Geological Survey, and the U.S. Army Corps of Engineers (USACE) evaluated water quality and historic oyster bar location. NOAA also commissioned an oyster population survey to determine the extent and density of today's oyster population.
The Plan targets 377 acres in Harris Creek for oyster restoration. Since 2011, 258 of those acres have been constructed, with funding from NOAA, Maryland Department of Natural Resources, and USACE. In 2015, an additional 57 acres of reefs are expected to be constructed, and additional seeding will take place. These reefs will be periodically monitored, with a final evaluation performed after six years to determine if several year classes have survived and meet the restoration criteria.
How Close Are Oysters in Harris Creek to Being "Restored"?