With flame-like gills protruding from its head and black spots spanning the length of its slimy, mud-colored body, the Neuse River waterdog is arguably one of North Carolina’s most charismatic species. Yet the giant salamander is on the path to extinction, a trend that North Carolina State University researchers are working to understand to help inform future management decisions.

“We know the Neuse River waterdog has experienced significant population declines across its range, but we still don’t fully know how to protect this species. That’s what my research is trying to figure out,” said Eric Teitsworth, a Ph.D. student in the Department of Forestry and Environmental Resources at NC State.

Teitsworth is working with Krishna Pacifici, a professor in the Department of Forestry and Environmental Resources at NC State, and the North Carolina Wildlife Resources Commission and the U.S. Fish and Wildlife Service to determine the distribution, occupancy and abundance of the Neuse River waterdog. 

Found nowhere else in the world outside the Neuse and Tar-Pamlico river basins of eastern North Carolina, the Neuse River waterdog is known or believed to occur in only 18 counties, with populations identified as far north as Durham and as far south as Greenville. The species, though still fairly common in some of these places, has suffered up to 50% declines in some areas across its range.

The Neuse River waterdog is currently listed as a “species of special concern” by the North Carolina Wildlife Resources Commission, meaning it cannot be legally killed, collected or possessed without a special permit. The U.S. Fish and Wildlife Service has proposed to list the Neuse River waterdog as “threatened” under the Endangered Species Act. The decision has yet to be finalized. 

Teitsworth said the decline of the Neuse River waterdog is concerning, because it is one of the region’s larger aquatic predators and helps to maintain ecosystem balance by preying on mollusks, insects and even small fish. His research will ultimately help the U.S. Fish and Wildlife Service create a “recovery plan” for the species.

“By learning where Neuse River waterdogs can still be found and what their main threats are, we can implement the appropriate conservation measures,” Teitsworth said.

Teitsworth is conducting population surveys across eastern North Carolina in an effort find out why the Neuse River waterdog is declining. It’s not an easy task. The species is fully aquatic and stays in the water for its whole life, making it incredibly elusive. As Teitsworth said, “They’re not easy to find.” 

From December to March, when the salamanders are most active, Teitsworth slips on waders on and steps in rivers and streams throughout the region to capture and count individuals. He has surveyed 130 locations since 2015, and the results are not promising: Neuse River waterdog populations are actively declining in nine counties, including Durham and Wake.

“I’m still conducting surveys, but the data I’ve collected so far suggest that some populations in the Neuse River around Raleigh and other parts of the Triangle have all but disappeared,” Teitsworth said. “You rarely find them there anymore.” 

Teitsworth said the species’ decline is likely a result of watershed instability and water pollution caused by increased rates of urban development. North Carolina is experiencing rapid growth that has brought housing development and road construction, both of which can negatively impact water quality in nearby streams and rivers. 

“Waterdogs prefer clean water that’s always flowing, and they’re very sensitive to change,” Teitsworth said. “When you have high rates of urban development, you get a lot of impervious surfaces that can increase the amount of water entering a stream after a storm. That can not only lead to increased variability in streamflow, but it can also cause increased sediment input that washes down and degrades habitat.”

Teitsworth added that large quantities of nutrient pollution, especially phosphorus and nitrogen, can also harm Neuse River waterdog populations. This type of pollution results from fertilizers and animal waste that’s washed from lawns, urban developed areas, farm fields and industrial meat production facilities into streams and rivers. 

While some of the same nutrients can be beneficial to aquatic life in small amounts, too many nutrients can contribute to excessive plant growth, algae blooms and low levels of dissolved oxygen in the water. The Neuse River waterdog and other aquatic animals need dissolved oxygen to survive. 

Teitsworth said riparian buffers, wetland remediation and other measures can help address sediment erosion and nutrient pollution. His research will ultimately help state and federal wildlife management agencies better understand where those measures might be most effective as they seek to help the Neuse river waterdog achieve healthy, self-sustaining populations.