Exoskeletal lesions in the male snow crab Chionoecetes opilio (Brachyura: Majidae) in the southern Gulf of St. Lawrence

• Main Authors: Khadra Benhalima, Mikio Moriyasu, Elmer Wade, Marcel Høbert
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Chionoecetes opilio; Snow crab
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.455.5747; http://www.vims.edu/research/departments/eaah/programs/crustacean/research/lobster_shell_disease/Lobster-Project-Resources/Publications/Lobster-pdf-files/1998 Benhalima et al. shell disease in snow crabs.pdf

Abstract: During population surveys of the snow crab, Chionoecetes opilio, conducted in the southern Gulf of St. Lawrence, the prevalence of males with multiple exoskeletal lesions was recorded. Histological, histopathological, and scanning electron microscope observations revealed that the progressive lesions of the chitinous exoskeleton, usually accompanied by blackening of the necrotic region, were caused by Gram-positive bacilli. Between 1993 and 1995, an average of 2.1 % of males larger than 60 mm carapace width (CW) in the southern Gulf of St. Lawrence were infected by bacteria. Infected animals were found to be concentrated in an area with a high density of male crabs in the southern Gulf of St. Lawrence. Adolescent males of <60 mm CW bore a heavily infected exoskeleton less frequently than adult males, and no significant difference in the rate of molting failure was observed between infected and uninfected groups of adolescent males. There is no evidence that the incidence of bacterial lesions is increasing in the southern Gulf of St. Lawrence. Résumé: Les relevØs au chalut de la population du crabe des neiges (Chionoecetes opilio) dans le sud du golfe du Saint-Laurent ont mis en lumiŁre la prØsence de lØsions multiples sur la carapace des animaux. Les observations histologiques et histopathologiques et lexamen au microscope à balayage ont rØvØlØ que ces lØsions progressives de la partie chitineuse de lexosquelette Øtaient causØes par des bactØries Gram positif et quil y avait noircissement des zones nØcrosØes. Entre 1993 et 1995, en moyenne de 2,1 % des mâles de taille supØrieure à 60 mm (largeur de la carapace, LC) dans le sud du golfe du Saint-Laurent Øtaient infectØs. Les animaux infectØs Øtaient concentrØs surtout dans les rØgions du golfe oø la population de mâles Øtait trŁs dense. Les mâles adolescents de taille supØrieure de 60 mm (LC) portaient moins de lØsions graves que les adultes et aucune diffØrence significative du taux de mortalitØ lors de la mue na ØtØ enregistrØe entre les mâles ...