Trial Background

VIMS Research

VIMS' program to monitor the current Virginia Seafood Council (VSC) trial provides an opportunity to investigate non-native oysters with full accountability and to advance knowledge of C. ariakensis as a candidate for introduction. Monitoring data can furthermore be used to develop an Environmental Impact Statement, an initiative now gaining momentum among Federal agencies.

The current monitoring program builds on more than eight years of VIMS research into the feasibility, potential benefits, and potential drawbacks of introducing non-native oysters to Chesapeake Bay. VIMS began studying non-native shellfish in 1995 at the request of the Virginia General Assembly. VIMS researchers began investigating the Suminoe oyster C. ariakensis in 1998. Comparisons between infertile C. ariakensis and the native oyster under a variety of salinities showed that C. ariakensis grew faster, better tolerated the oyster diseases MSX and Dermo, and tasted just as good. All field trials have employed sterile individuals to ensure against accidental introduction of non-native oysters to Chesapeake Bay.

The early VIMS field trials showed that hatchery-reared C. ariakensis hold promise for rebuilding the commercial oyster industry in Virginia and Maryland through aquaculture. At the same time, there are strong concerns over using non-native species in light of past ecological impacts. VIMS addressed these concerns in a November 2001 position statement.

Prior Industry Field Trials

The Virginia Seafood Council (VSC) has previously run two commercial trials of C. ariakensis, both with promising results. The information from these trials is largely qualitative. In 2000, 6,000 genetic triploids were deployed among six growers and all oysters were deployed in clam relay cages on the bottom. Duration of the trial was one year.

In 2001, VSC began another test in mid-summer with about 60,000 triploids. These were distributed among 13 growers using a variety of methods, from bottom trays to Taylor floats, and across representative salinities found in Virginia. Some successful test marketing was accomplished. As in the first trial, results were primarily qualitative.

The Current VSC Trial

The current VSC field trial was originally scheduled to deploy about a million triploid C. ariakensis equally among 10 commercial growers. The goal of the trial is to demonstrate economic feasibility for large-scale aquaculture of triploid C. ariakensis. A production delay, followed by Hurricane Isabel, led two growers to relinquish their roles in the trial. The remaining eight growers each began to deploy about 100,000 triploid C. ariakensis on September 29, 2003. The growers will hold the oysters until they reach market size and then market them in various ways. VIMS will track costs and labor throughout.

The VSC test uses oysters that were made sterile by crossing genetically modified males with normal females. This brood stock is held at VIMS' Gloucester Point hatchery using standard quarantine practices. Seed oysters will be grown to 20mm, the starting size for the 2003 industry trials.

Note: VIMS is mandated in the Codes of Virginia to provide impartial scientific advice to the Virginia Marine Resources Commission (VMRC), the regulatory body for all decisions concerning non-native species in Virginia waters. VIMS supported the Seafood Council's request to VMRC for a commercial-scale test, based on its adherence to VIMS' published set of objective biosecurity guidelines. However, VIMS cannot be viewed as an entirely independent body during the VSC field trials because the Aquaculture Genetics and Breeding Technology Center (ABC) at VIMS will be supplying the sterile non-native oysters that VSC will use in its study. VIMS has formed an independent oversight committee in recognition of this fact.