How Will Brook Trout Respond To Climate Change?

As the climate changes, scientists around the world are trying to figure out how plants, animals and even people will be affected. One scientist in West Virginia is conducting an experiment to find out how well a fish native to Appalachian streams might survive.

Biologist Than Hitt works at the U.S. Geological Survey Leetown Science Center in Jefferson County, West Virginia, where scientists explore everything from declining fish and mussel populations to the increasing presence of intersex fish in the nation’s waterways. Hitt has just started a new research project: trying to determine how climate change might affect the brook trout.

“These trout were here over the course of multiple glaciation events,” Hitt said. “They’ve adapted to cold water streams that quite frankly are jeopardized by the change in climate that we expect over the next 30 to 50 years.”

“So the southern Appalachian brook trout can be a canary in the coal mine for us to understand how streams are responding to climate change,” he added.

There are 12 large round blue tanks in the lab: four sets of three connected tanks so the fish can travel from one to another. It’s basically a room full of giant aquariums set up so Hitt can control things like temperature, water chemistry, flow rate, food supply during the two month study.

“We want to understand what the relative importance of thermal stress is and interactions with other stressors like changes in invasive species showing up or changes in prey availability or other factors that we can control.”

The first invasive species these brook trout will encounter is the brown trout, which is native to Germany.

“Brown trout are a prized game fish in some places and they also are known for displacing native brook trout,” Hitt said. “It’s not clear though how that displacement effect interacts with the temperature effect. In warming streams maybe that’s where brown trout are able to displace brook trout fully whereas in the colder streams perhaps they’re able to coexist and persist in the same stream reach.”

Aside from conducting controlled experiments in these tanks at the lab in Leetown, West Virginia, Hitt will do field work in the Shenandoah National Park in Virginia and the Delaware Gap National Recreation Area. Partners in the project include the USGS Chesapeake Bay Program, the National Park Service and several state divisions of natural resources.