Vibrio is a naturally occurring bacteria present in high levels in seawater when temperatures are warm. It can cause serious illness in humans. The National Shellfish Sanitation Program requires Delaware to implement plans to reduce the risk of Vibrio illnesses from oysters harvested in Delaware.
Vibrio — Vibrio parahaemolyticus (V.p.) — can become concentrated in the flesh of oysters, which feed by filtering nutrients out of the waters that surround them. Oysters are commonly eaten whole and raw or partially cooked, so pathogens like Vibrio are not destroyed by cooking.
Vibrio can also cause infections of skin wounds that contact seawater or seafood.
By following Vibrio Control Plans and practicing additional measures such as on-board icing of oysters, commercial oyster harvesters can increase the safety of oysters for consumers. The plans are provided here for reference by the commercial oyster industry. Recreational harvest of oysters is illegal year-round in Delaware.
The Vibrio Control Plan for oysters harvested from Rehoboth Bay and Indian River Bay establishes time and temperature requirements such as on-board shading and icing from June 1 through Sept. 30.
The Vibrio Control Plan for oysters harvested from Delaware Bay prohibits harvest from June 1 through Aug. 31. The DNREC Division of Fish and Wildlife already establishes harvest seasons that do not include these months.
No Vibrio Control Plan is necessary for clams harvested from Delaware.