Complex etiologies of emerging diseases in lobsters (Homarus americanus) from Long Island Sound

Abstract

Several diseases have recently emerged in lobsters (Homarus americanus) from Long Island Sound (LIS). Various stressors have been implicated as contributory factors, including increased bottom temperatures, extensive eutrophication with commensurate hypoxia, storm-induced thermal destratification, possible exposures to pesticides and metals, and fishery-induced stressors. Such stressors increase host susceptibility by weakening the host immune defenses and act to increase the transmission and severity of pathogens. The lobster mortality in western LIS in 1999 was linked to Neoparamoeba pemaquidensis, but a complex of stressors resulted in outright mortality from hypoxia or consequent immune suppression that increased susceptibility to the ameba. Similar stressors have been implicated in the etiology of epizootic shell disease and calcinosis. The role of environmental stressors has been hard to delineate, but recent declines in landings indicate that epizootic shell disease has had a negative impact on the lobster population in LIS. Calcinosis, blindness, and hepatopancreatitis are indicators of continued exposure to anthropogenic stressors, but their etiologies remain undetermined. More research is needed to understand emerging diseases, their complex etiologies, and their effects on the lobster population.