Most people would agree: River otters are adorable. But beyond their playfulness, the otters have an important role in determining the health of a river system.
At N.C. State University, scientists this year released studies on river otters that they plan to use as baselines for future research. The first study examined the toxicological effects that metals, such as mercury, cadmium, arsenic and lead, are having on the otters.
North Carolina’s river otter populations are relatively healthy compared with populations in other areas of the United States and Canada, said Chris DePerno, a professor in N.C. State’s Fisheries, Wildlife and Conservation Biology program.
But the findings in otters don’t mean the state’s lakes, rivers and streams are pristine. North Carolina has a statewide advisory warning for consuming fish that contain mercury, as well as warnings for many water bodies with fish containing high levels of mercury, polychlorinated biphenyls (PCBs), hexavalent chromium, dioxins and arsenic.
River otters are fierce predators that eat many creatures further down the food chain. That means heavy metals bioaccumulate and biomagnify in them. In other words, the more fish the otters eat, the more heavy metals build up in their systems.
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