October 3, 2012
Health Of Marine Ecosystems Associated With Health Of Manatees
April Flowers for redOrbit.com - Your Universe Online
A team of scientists, led by George Mason University, have conducted a long-term study of manatees which may be a benchmark in determining health threats to marine mammals. The study, which ran over ten years in Belize, examined the behavioral ecology, life history and health of manatees in an area relatively undisturbed by humans.“Manatees are the proverbial ℠canaries in the mineshaft,´ as they serve as indicators of their environment and may reflect the overall health of marine ecosystems,” says Alonso Aguirre, executive director of the Smithsonian-Mason School of Conservation.
The results of the new research were published recently in the journal PLoS One. The research was a collaborative effort between George Mason University, the Smithsonian-Mason School of Conservation, the University of California, Davis, the United States Geological Survey (USGS) and Sea to Shore Alliance.
The manatees serve as early warning indicators of environmental change, making them what Aguirre calls a "sentinel species." Manatees can indicate a severe environmental change before other marine species or even humans are affected because of their high susceptibility to some environmental stressors, and their high resistance to others.
“Studying them may help us predict a change that has the potential to be devastating to an ecosystem or a habitat if left unaddressed,” Aguirre says.
The site of the study is a small fishing community in southern Belize that is beginning to prosper and gain more tourist traffic. The long-term study allowed the researchers to see the effects of human influence, more stress, boat strikes and other changes in what had been a relatively pristine area with low human impact.
Aguirre and others like him are focusing on uncovering the systemic health threats to marine vertebrate species, including marine mammals, as they relate to marine ecological health. This is a concern because there have been an unprecedented number of emerging and re-emerging diseases in dolphins, coral reefs and marine turtles in recent years.
“The single species approach may provide a series of “snapshots” of environmental changes to determine if animal, human or ecosystem health may be affected,” says Aguirre.
The research team captured the manatees and tagged them for tracking before releasing them back into their habitats. During the capture times, health assessments were conducted based on clinical exams, ultrasonic fat measurements, hematology, blood biochemistry and waste product analyses. Between 1997 and 2009, the scientists collected close to 200 blood samples, and aerial surveys were conducted by helicopter twice a year to monitor population sizes.
Aguirre said, “This longterm study, unique within marine mammals, provides insight on the baseline health of this species now threatened primarily by human encroachment, poaching and habitat degradation. This study is a benchmark aiding in early disease detection and the current environmental impacts affecting the epidemiologic patterns in the manatees of this region.”
The study will also provide some initial tools to explore the broader application of manatees as sentinel species of nearshore ecosystem health. The next goals for the team are a conservation plan for the manatees, extend protection of migratory paths and areas where manatees live and work with local populations as well as tourists to educate them about conservation activities.