|Oyster Restoration in the Tred Avon River|
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
Partners including the Maryland Department of Natural Resources, National Oceanic and Atmospheric Administration, U.S. Army Corps of Engineers Baltimore District, and Oyster Recovery Partnership are teaming up on a project to restore native oysters to the Tred Avon River on Maryland's Eastern Shore. The project includes:
Building and enhancing oyster reefs is a complex process that involves comprehensive studies before, during, and after construction efforts. Using scientific analysis developed with cutting-edge sonar equipment, the Maryland Interagency Oyster Workgroup updated its draft "Blueprint" for oyster restoration in April 2015; this document describes when and where reefs will be constructed or enhanced. An important part of the Blueprint is maps that show where shell or granite substrate and/or oyster seed are proposed to be placed.