[Chesapeake Quarterly masthead]
Volume 4, Number 3
Table of Contents
Download pdf

A Non-Native Oyster:
Assessing a Potential Introduction

By Erica Goldman

C. ariakensis in a hand

Decision Timeline
for C. ariakensis

Severe disease impacts native oyster; 1987-88 Maryland harvest drops to 363,259 bushels
Oyster industry requests introduction of non-native oysters
National Academy of Sciences agrees to study the implications of introducing C. ariakensis
March 2002
Chesapeake Bay Program adopts policy on non-native oysters,VIMS conducts tests on C. gigas
March 2003
Maryland's oyster harvest for 2003-04 ends at record low of 53,000 bushels
August 2003
National Academy of Sciences report released
January 2004
Army Corps launches EIS; notice in Federal Register
Spring 2005
Draft EIS originally due; delayed to gather additional information
June 2006
Decision Point: publish draft of EIS or determine if more information is needed
late 2006
Approximate timeframe for final decision on determination to release C. ariakensis

Elizabeth North's oyster model will serve as one of many tools to inform the Environmental Impact Statement (EIS) currently being conducted by the states of Maryland and Virginia, along with federal partners. The ultimate goal of the EIS is to "identify a strategy and subsequent actions that will successfully re-establish an oyster population in Chesapeake Bay to a level of abundance that would support sustainable harvests comparable to harvest levels during the period 1920-1970."

The EIS is considering one so-called proposed action, to introduce reproducing populations of the Asian oyster (Crassostrea ariakensis) to the Bay and continue restoration efforts for the native oyster, and seven alternatives to that action. These alternatives include recommendations such as a harvest moratorium, improved aquaculture, and the introduction of sterile (triploid) populations of the non-native oyster.

Likely in late 2006, the states will decide whether to introduce the non-native oyster to the Chesapeake. At each level, decision makers will evaluate the available information and weigh the risks and benefits. They will also look closely at the uncertainty associated with these predictions — carefully considering that predicting the future of an ecosystem is inherently an uncertain enterprise.

Decision makers will weigh multiple levels of scientific, economic, and cultural analysis in their final assessment. Models, combined with experimental research on oyster disease and human health, will help predict how the introduced species would fare, as well as evaluate potential risks to the ecosystem. Other research will help quantify potential benefits to the ecosystem of a restored oyster population, such as reduced levels of nitrogen and phosphorus, and will evaluate effects further up the food chain, such as oyster interactions with blue crabs, fish, and birds that eat oysters. An economic analysis quantifies the benefits to the industry of a restored oyster fishery and estimates the economic value of environmental improvements to the Bay that could result from a healthy oyster population. Finally, a cultural analysis evaluates stakeholder attitudes to a restored fishery, to potential environmental improvements, and to the risks of introducing a non-native species.

While the ultimate decision on the outcome of the EIS rests with the states, the agencies involved — the Maryland Department of Natural Resources (DNR), along with the Virginia Marine Resources Commission, the Army Corp of Engineers, National Oceanica and Atmospheric Administration, Environmental Protection Agency and the U.S. Fish and Wildlife Service — have engage7 scientists and several high-level scientific advisory panels at many stages of the EIS process.

It is a complex project, says Tom O'Connell, DNR Project Manager for the oyster EIS. "The Administration is wholeheartedly behind oyster restoration, but we are committed to having a scientifically defensible EIS," he says.

With the goal of "scientific defensibility," DNR aims to conduct the EIS in a rigorous and transparent manner. On the research side, the agency has funded 12 projects to address eight specific ecological risk factors identified in a report released in 2003 by the National Academy of Sciences. North's larval transport model, one of the projects funded, will help address four of the eight risk factors — re-establishment of a self-sustainable oyster (either species) population, re-establishment of oyster reefs (either species), distribution of oysters in the Bay (either species), and dispersal of the Asian oyster beyond the Chesapeake Bay.

To help advise researchers and evaluate the quality of their work, DNR also appointed a high level Independent Advisory Panel in the fall of 2004. This body is comprised of top university scientists, including two members of the earlier panel that produced the National Academies report. The Advisory Panel is charged to:

  1. Review the adequacy of data and assessments used to identify the ecological, economic, and cultural risks and benefits and associated uncertainties for each EIS alternative.

  2. Advise states of any incomplete information relevant to reasonably foreseeable significant adverse impacts on the human environment that the Panel considers essential to a reasoned choice among alternatives.

  3. Advise states on the degree of risk that would be involved for each EIS alternative if a decision were made based on the available data and assessments.

After the Panel has reviewed the final reports from each of the projects underway, it will issue a report to DNR recommending either the proposed action, one of the alternatives, or some combination of alternatives. Although the states are not legally obligated to act on the Panel's findings, they will "in all probability" follow their recommendations, according to panel member Michael Roman, a biological oceanographer and director of the University of Maryland Center for Environmental Science Horn Point Laboratory.

"Decision makers will take what we have to say very, very seriously," says Brian Rothschild, chair of the Oyster Advisory Panel and dean of the University of Massachusetts at Dartmouth's intercampus Graduate School of Marine Sciences and Technology. "But decision makers live in a political climate," he says. "They also need to take into account how people feel about the issues."

Top of Page

[Chesapeake Quarterly]
Other Issues

[Chesapeake Quarterly Bar]
[Maryland Sea Grant][NOAA]