Oyster Restoration

Why Restore Oysters?

World-wide oyster habitat and populations have declined by an estimated 85% worldwide in the last 100 years (Beck et al. 2011). In the United States, there has been an estimated 88% decline in oyster biomass, with oyster populations being strongly affected in estuaries along the Atlantic coast. "The most dramatic losses of Eastern oyster habitat were recorded from the northeast Atlantic coast, with less than 6 percent of historic extent remaining..." (Zu Ermgassen et al. 2012). Significant population declines are due to a number of reasons including: over-harvesting, not returning suitable substrate (oyster shell) back to the water, habitat loss, sedimentation, disease and poor water quality (Wilberg et al. 2011). In response to worldwide population loss of a keystone species, scientists have made significant efforts to restore oyster reefs.

Eco-Benefits

One oyster filters around 30 gallons of water a day, which helps to improve water quality
Oysters’ excellent filtering abilities lower turbidity allowing light penetration for eelgrass growth
Shells help prevent ocean acidification on a local level because when shells decompose calcium carbonate (basic) is released back into the water column to help stabilize pH
Oyster reefs provide habitat for numerous types of fish, shellfish, and crustaceans, while acting as a shoreline buffer against erosion

Shimmo Creek Oyster Restoration Project

In June of 2017 and 2018, the Oyster Restoration Project in Shimmo Creek was constructed. It is a subtidal, one acre area consisting of 8 loose shell rows composing of 100,000 pounds of recycled oyster and quahog shell with 7 rows of bare bottom in between. Shell deployment was made possible by many volunteers including local non-profit organizations, students, and community members.

Project Goals

Restore populations of the native oyster species, Crassostrea Virginica, in Nantucket waters in order to establish a healthy coastal ecosystem providing habitats to support an array of species.
Stock oyster spat on shell grown at the Brant Point Shellfish Hatchery and a determined amount of broodstock for several years in order to supplement natural recruitment until the reef persists as self-sustaining with multi-year age classes.
Establish an educational platform for local and visiting scientists, students, and the community to study the ecological benefits of a small-scale oyster reef. Topics may include but are not limited to water quality, species biodiversity, and shoreline stabilization.
Long-term monitoring of the oyster reef including oyster size frequency distribution, oyster densities, reef height, and sex ratio will provide information about growth, recruitment, survival of cohorts, and reef success.

Data collection (follows the Oyster Habitat Restoration Monitoring and Assessment Handbook): Seasonal water quality sampling, spat collectors-natural recruitment, benthic survey, seine net survey, fish traps, submerged aquatic vegetation densities, oyster density, oyster size-frequency distribution, sex ratio, reef areal dimensions, reef height, and percent cover of substrate.