Baltimore, Md. (January 24, 2011) A research effort designed to prevent the introduction of viruses to blue crabs in a research hatchery could end up helping Chesapeake Bay watermen improve their bottom line by reducing the number of soft shell crabs perishing before reaching the market. The findings, published in the journal Diseases of Aquatic Organisms, shows that the transmission of a crab-specific virus in diseased and dying crabs likely occurs after the pre-molt (or 'peeler') crabs are removed from the wild and placed in soft-shell production facilities.
Crab mortality in soft shell production facilities is common, where it is typical for a quarter of all crabs to perish. Scientists attribute this high loss to the pressures crabs face as they are harvested, handled and placed in the facilities. When combined with the large number of animals living in a confined area, the potential for infectious diseases to spread among the crabs increases.
The team, led by University of Maryland Center for Environmental Science (UMCES) researchers, developed an innovative way to identify this crab virus solely by isolating its genetic material. Local watermen working in the soft-shell industry provided crabs to the Baltimore-based Institute of Marine and Environmental Technology (IMET) for examination.
In the laboratory, the researchers investigated the possible role of viruses in the soft shell crab's mortality by exploiting the unique physicochemical properties of the virus genome, which consists of double stranded RNA (distinct from the double stranded DNA that makes up crab and human genomes). They first extracted nucleic acids from potentially infected crabs then enriched virus genomes, allowing them to more easily find the virus. Once identified by its genome, the reo-like virus was later visualized by microscopy by collaborators at the NOAA Oxford lab.
"The molecular tools we developed during this study allow us to
|Contact: Christopher Conner|
University of Maryland Center for Environmental Science