Published online before print December 15, 2010, doi: 10.1177/0300985810388525 Veterinary Pathology May 2011 vol. 48 no. 3 676-690
Marine Mammals as Sentinel Species for Oceans and Human Health
1Georgia Aquarium, Atlanta, Georgia, and Division of Comparative Pathology, Department of Pathology, School of Medicine, University of Miami, Miami, Florida
Gregory D. Bossart, VMD, PhD, Georgia Aquarium, 225 Baker St. N.W., Atlanta, GA 30313
Abstract
The long-term consequences of climate change and potential environmental degradation are likely to include aspects of disease emergence in marine plants and animals. In turn, these emerging diseases may have epizootic potential, zoonotic implications, and a complex pathogenesis involving other cofactors such as anthropogenic contaminant burden, genetics, and immunologic dysfunction. The concept of marine sentinel organisms provides one approach to evaluating aquatic ecosystem health. Such sentinels are barometers for current or potential negative impacts on individual- and population-level animal health. In turn, using marine sentinels permits better characterization and management of impacts that ultimately affect animal and human health associated with the oceans. Marine mammals are prime sentinel species because many species have long life spans, are long-term coastal residents, feed at a high trophic level, and have unique fat stores that can serve as depots for anthropogenic toxins. Marine mammals may be exposed to environmental stressors such as chemical pollutants, harmful algal biotoxins, and emerging or resurging pathogens. Since many marine mammal species share the coastal environment with humans and consume the same food, they also may serve as effective sentinels for public health problems. Finally, marine mammals are charismatic megafauna that typically stimulate an exaggerated human behavioral response and are thus more likely to be observed.
As the effects of climate change and potential environmental degradation are debated and better characterized, worldwide concern is being raised about the health of the earth?s aquatic ecosystems.40,148,206,212 The long-term consequences of environmental change on aquatic ecosystems are not well characterized but are likely to include aspects of disease emergence in aquatic plants and animals.206 In turn, these emerging diseases may have epizootic potential, zoonotic implications, and a complex pathogenesis involving other cofactors such as anthropogenic contaminant burden, genetics, and immunologic dysfunction.30,181 Emerging diseases have themselves become new drivers of environmental change since they can cause extinction of endangered species; alter the ratios of predators, prey, competitors, and recyclers necessary for healthy, well-functioning ecosystems; and alter habitat already threatened by the emergence of discontinuities (ie, habitat fragmentation) and climate change.62
Ocean health is inextricably linked to human health on a global scale as well. Connections between the health of humans, animals, and the environments in which they live are well recognized and recently have been referred to as ?one health, one medicine.? The ?one health, one medicine? worldwide strategy for expanding interdisciplinary collaborations and communications in all aspects of health begins to address these critical relationships.
The concept of marine sentinel organisms provides one approach to evaluating aquatic ecosystem health. Such sentinels are used to gain early warnings about current or potential negative impacts on individual- and population-level animal health.29 In turn, such warnings permit better characterization and management of these impacts that ultimately affect human and animal health associated with the oceans. Marine mammals are described as prime sentinels because many species have long life spans, are long-term coastal residents, feed at a high trophic level, and have large blubber stores that can serve as depots for anthropogenic chemicals and toxins.7,15,29,30,110,111,154,155,184,234 Finally, marine mammals are charismatic megafauna that typically stimulate an exaggerated human behavioral response and are thus more likely to be observed.21 Therefore, health concerns that affect these species may make humans more likely to pay attention to ocean health issues.
