Lobster shell disease
|Shell disease is caused by bacteria that invade from the outside of the lobster through pores in its cuticle-or the outermost layer of the shell-that cannot be seen by the naked eye. There is a range in the severity of the disease from shallow pits that eat away at the cuticle and cause those unsightly black spots to ulcerations-holes that fully penetrate the shell, causing the shell and the membranes underneath it to fuse together. This can stop the lobster from releasing its shell and can cause it to become stuck during the molting process and die (http://seagrant.gso.uri.edu/factsheets/lobster_shell_disease.html). (Marine Disease Pathology & Research Consortium (www.msrc.sunysb.edu/ ~MDPC/gallery.htm))|
Ann Tarrant, John Stegeman (WHOI Biology), Judy McDowell (WHOI Biology), Diane Cowan (The Lobster Conservancy)
From a historical, cultural, ecological and economical point-of-view, one exceptionally important crustacean species in the Northeast marine environment is the American lobster, Homarus americanus. The lobster fishery is the most valuable fishery on the Atlantic coast of both theUnited States (2003 landings in NE-USA valued at $286 million) andCanada and it is presently under enormous anthropogenic and environmental stress. Two alarming facts are the huge decline in lobster catches inSouthern New England (77% decline from 1999 to 2003 in Lobster Management Area 2), and the increased incidence of lobster epizootic shell disease (up to 33%, on average, inNew Englandwaters). The recent lobster population declines have been attributed to a variety of factors, including elevated temperatures, anoxia, paramoeba infestation, and exposure to pesticides and other chemicals. To date, the mechanisms behind epizootic shell disease and the decline in lobster catches remain unknown.
We are using global and targeted molecular approaches to identify genes that are differentially regulated in healthy versus shell-diseased lobster. Specifically, we will use suppressive subtractive hybridization (SSH) to identify candidate genes involved in shell disease, and quantitative real-time PCR to quantify the expression of specific genes. Our approach will determine the role (if any) of the hormone and immune systems, molting, energy and xenobiotic metabolism, and shell development in lobster shell disease. To the best of our knowledge, this will be the first study to use measures of gene expression to investigate lobster shell disease. This project is funded by WHOI SeaGrant. We were recently funded to continue our work on lobster shell disease in 2007-2009 through a grant provided by the New England Lobster Disease Research Initiative (New England Lobster Research Initiative website ).