28th ANNUAL EASTERN FISH HEALTH WORKSHOP April 21-25, 2003 A Geographically Based Comparison Of Carapace Erosions And Bacteria Cultured From Lesions In Homarus americanus Andrea C. Hsu1, Roxanna M. Smolowitz2, Andrei Y. Chistoserdov3, and Hemant M. Chikarmane2 1Boston University Marine Program, 7 MBL St., Woods Hole, MA 02543; 2Marine Biological Laboratory, 7 MBL St., Woods Hole, MA 02543; 3University of Louisiana, Lafayette, Department of Biology, Lafayette, LA 70503 During the last six years, shell disease of the American lobster Homarus americanus has been found at high levels along the New England coast.  This study utilized a combination of histological analysis, scanning electron microscopy (SEM), and denaturing gradient gel electrophoresis (DGGE) to describe and define bacterial cells on the infected carapace of wild-caught lobsters.  Diseased lobsters used in this study were collected from Eastern Long Island Sound, New York, northward toward Cape Cod Bay, Massachusetts, but control animals were obtained from Maine. Histopathologically, the carapace matrix was usually absent or lattice-like cuticular remnants were attached to underlying less degraded cuticle.  Bacteria were the predominant organisms found at the leading edges of erosions.  The SEM analysis revealed and statistical tests verified that three separate morphological types of bacteria were present in shell lesions.  Halo-like holes surrounding all bacterial types suggested that boring was their causative mechanism for degrading the lobster carapace.  Bacteria were the dominant organisms on both the surface and leading edges of lesions.  Preliminary DGGE data indicated that there were 14 independent phylotypes of bacteria present in lobster lesions.  At least two phylotypes were found in all diseased lobsters, but not in the control animals.  Combined results from histology, SEM, and DGGE provided evidence that a consortium of bacteria may cause New England epidemic shell disease.  (Funded by WHOI/MIT Sea Grant Industry Fellowship and NY Sea Grant). Return to 28th Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page