Ecological Risks Associated with Oyster Restoration Options for Chesapeake Bay

Abstract

ABSTRACT Ecological risk assessments were conducted as part of the Programmatic Environmental Impact Statement designed to evaluate costs and benefits of alternative approaches to oyster restoration in Chesapeake Bay, USA, including the intentional introduction of a non-native Asian oyster species. A relative risk model was used to evaluate alternatives involving both the native Eastern oyster and the non-native species. Effects of options were examined for a diverse set of ecological resources and conditions for the Bay including oysters, submerged aquatic vegetation, phytoplankton, zooplankton, benthic invertebrates, blue crabs, fish, wildlife receptors, dissolved oxygen, and total suspended solids. A weight-of-evidence method based on available scientific evidence was also used to answer a set of questions developed by a science advisory panel. There was low risk that the Asian oyster would not provide ecosystem services similar to those afforded by the Eastern oyster; however, there is moderate to high risk that the Asian oyster would interact with and compete with the Eastern oyster. The potential for introduction and spread of diseases from the Asian oyster to other species in the Bay is considered negligible, but there is high risk that the Asian oyster would disperse outside of the Bay.