Stevens Bradley G
School of Marine Science and Technology, University of Massachusetts Dartmouth, 706 S. Rodney French Blvd., New Bedford, Massachusetts 02744, USA.
Dis Aquat Organ. 2009 Dec 22;88(1):25-34. doi: 10.3354/dao02135.
The incidence of epizootic shell disease in American lobster Homarus americanus has increased in southern New England, U.S.A., in the last decade, but few longitudinal studies have followed the disease progress in individual lobsters or demonstrated direct effects on mortality or growth. Diseased lobsters were held in the laboratory for 1 yr, and the progression of disease and its effects on molting, mortality, and growth were monitored. A quantitative disease index (QDI) was developed by measuring disease lesions in digital images of the carapace and expressing the result as a proportion of shell area. Some lobsters died due to high temperatures, but at least 13 of 55 lobsters (24%) died as a direct result of disease-related problems, mostly during molting, and there was a significant relationship between mortality and high values of the QDI. Lobsters that molted successfully were free of disease lesions, but many had exoskeletal deformities. There was no relationship between pre-molt size and disease severity, but molt increment was significantly correlated with premolt carapace length (CL) and negatively correlated with QDI. However, percentage growth was negatively correlated with QDI, but not with pre-molt CL. These significant lethal and sublethal effects of epizootic shell disease should be considered in lobster management.
在过去十年中，美国龙虾美洲螯龙虾的流行性外壳疾病发病率在美国新英格兰南部有所上升，但很少有纵向研究跟踪个体龙虾的疾病进展情况，也没有证明该疾病对死亡率或生长有直接影响。患病龙虾在实验室中饲养了1年，监测疾病的进展及其对蜕皮、死亡率和生长的影响。通过测量头胸甲数字图像中的疾病损伤，并将结果表示为壳面积的比例，制定了一个定量疾病指数（QDI）。一些龙虾因高温死亡，但55只龙虾中至少有13只（24%）因疾病相关问题直接死亡，主要发生在蜕皮期间，死亡率与高QDI值之间存在显著关系。成功蜕皮的龙虾没有疾病损伤，但许多龙虾有外骨骼畸形。蜕皮前的大小与疾病严重程度之间没有关系，但蜕皮增量与蜕皮前头胸甲长度（CL）显著相关，与QDI呈负相关。然而，生长百分比与QDI呈负相关，但与蜕皮前CL无关。在龙虾管理中应考虑流行性外壳疾病这些显著的致死和亚致死效应。
