Conservation efforts in Western Pennsylvania have led to the remarkable restoration of the river otter. It means not only the return in numbers of one of the most delightful and popular of our native wildlife, but the significant improvement of our waterways in the last 50 years.

Until the 19th century, native river otters lived in relatively healthy numbers along the banks of the Allegheny River, as well as every major river system in Pennsylvania.

Centuries of hunting by fur traders had reduced the numbers, however, and then 19th century industrialization severely harmed the river ecosystem and greatly reduced the otter population. The last otter in the Allegheny River was reported in 1899. With the exception of a few watersheds in the Poconos, by the early 1900s, wild otters had largely vanished from Pennsylvania, a marker of how polluted and degraded the state’s river systems had become.

“We went from a primarily forested state to an agricultural state,” Tom Keller, furbearer biologist at the Pennsylvania Game Commission, told the Allegheny Front. “And then we start to see a lot of our water sources start to be dammed up for a variety of different mills and tanneries.”

Otters are considered an “indicator species,” which means their numbers and health signal the overall health of a river ecosystem. They need a lot of food, particularly small fish and crustaceans, which are themselves sensitive to water quality. Degraded ecosystems mean fewer of these creatures, which means not enough food for otters to thrive. The advance of pollution in a river can be traced in the decline of its otters.

“They’re a sign of a healthier landscape,” Pennsylvania Department of Conservation and Natural Resources environmental education specialist Dale Luthringer told the Post-Gazette a decade ago. “Like the eagles that people see frequently now. They wouldn’t be in the river if there weren’t fish to eat.

Efforts by the Game Commission to protect the otters through regulation in 1952 by closing otter trapping season did little to increase their population because it did not address the causes of the degradation of the rivers’ ecosystems.

It ultimately took legislation reducing pollution to recreate rivers otters could live in. For example, the federal Surface Mining Control and Reclamation Act forced coal mining companies to stop abandoning mines with no regards for the millions of gallons of toxic runoff they would create in the years and decades to come. The Clean Water act and other legislation further strengthened these protections.

Soon nonprofits and government agencies were funding and building water and drainage treatment systems, which little by little cleared the water. By 1990, conditions had improved enough that researchers from the Wild Resource Conservation Program, the Game Commission, and Penn State University slowly began reintegration efforts, releasing river otters, Lutra canadensis, in several watersheds, including Tionesta Creek, a tributary of the Allegheny, and the Youghiogheny River, a tributary of the Monongahela.

The Allegheny Front reports that 35 years later, the reintegration program is a resounding success, with otters showing up in unexpected places, far from the original release points. While, generations ago, these agile and popular animals indicated that human interventions had fouled Pennsylvania’s river ecosystems, today they indicate the opposite: that human efforts can restore rivers, a change from which we benefit even more than the otters.

— Pittsburgh Post-Gazette via TNS