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Roseovarius Oyster Disease 

Scientific Name:

Roseovarius crassostreae

 Common Name:

Roseovarius Oyster Disease (also: Juvenile Oyster Disease) 

 Disease Type:

Marine alpha-protobacterium

 Affected Organisms

Hatchery-raised Eastern oysters (Crassostrea virginica)

 Native Range:

Currently unknown

 Established Range:

Maine to New York

 Established in Rhode Island?

Yes, throughout Narragansett Bay

 Date and Location of Introduction:

1984, Maine

 Method of Introduction:



This disease is characterized by heavily stunted growth in juvenile oysters, as well as lesions, mantle recession, unequal shell growth, and brown rings on the inside of shells. Mortality rates of 60% or higher are common.

 Detection and Diagnosis:

This disease can be diagnosed through a microscopic examination of tissue sections.


While Roseovarius Oyster Disease has no negative effect on humans who consume infected oysters, it can have negative effects on the seafood and aquaculture industries when large-scale oyster die-offs occur.


Roseovarius Oyster Disease can be suppressed by growing oysters in low salinities (less than 10 ppt) and deploying oyster seed early in the season.


 Works Cited:

Bower, S.M. 2010. Synopsis of Infectious Diseases and Parasites of Commercially Exploited Shellfish: Juvenile Disease of Eastern Oysters. Fisheries and Oceans Canada.

Sunila, I. 2007. Roseovarius Oyster Disease. Connecticut Department of Agriculture, Bureau of Aquaculture and Laboratory Milford, CT.