Precautionary measures initiated following detection of invasive round goby fish

DNA found at Champlain Canal’s second lock in Halfmoon triggers extra monitoring

By Zachary Matson

A positive detection of invasive round goby DNA north of the Champlain Canal’s second lock in Halfmoon triggered additional monitoring and changes to canal operations as a precaution, state officials announced Friday.

State and federal agencies have been working to monitor the invasion front of round goby, which are native to the Caspian and Black seas and have spread broadly throughout the Great Lakes after being introduced sometime around 1990. 

Researchers with the U.S. Geological Survey collected the environmental DNA (eDNA) samples this month, finding a single positive detection above Lock C-2 near Mechanicville, where the canal coincides with the Hudson River. The eDNA method identifies residual genetic material in air, soil and water associated with specific species and is a growing tool for researchers and environmental managers.

While they have not captured any actual fish in the area, the eDNA result is an early signal that goby have continued to make progress toward the Lake Champlain basin, where government officials, environmentalists and scientists fear the fish could become the lake’s newest invader and wreak havoc on the sprawling lake’s fragile ecology. 

Limiting lock access, other procautions

The Department of Environmental Conservation and Canal Corporation announced that effective June 24 the canal would limit to three times a day the number of time locks C-1 and C-4 would open for recreational vessels. They also plan to expand the use of “double draining,” which flushes stronger currents of water out of the locks to deter fish passage when open, from locks C-1 and C-2 to include locks C-3 and C-4. 

The DEC has announced the following canal changes: 

• Lock C-1, Waterford, Lock C-2, Halfmoon, Lock C-3, Mechanicville, and Lock C-4, Stillwater, starting Monday will pass recreational vessels three times daily; 
• Lock C-1 will pass northbound traffic and Lock C-4 will pass southbound traffic daily at 8 a.m., 10 a.m., and 2 p.m.;
• Locks C-2 and C-3 will pass traffic when the vessels arrive from Locks C-1 or C-4. This schedule will remain in place until further notice and is subject to change depending on results of continued sampling; 
• Vessels will not be allowed to moor overnight at Lock C-1 and Lock C-4 approach walls.  

The management precautions are part of a response plan officials adopted in 2023 outlining increasingly protective measures if monitoring indicated goby continued to move toward the Champlain watershed. Researchers are collecting and processing more eDNA samples to see if other positive detections increase confidence the fish has advanced, as well as searching for round goby in the water. 

Previously, goby have been captured and detected with eDNA downstream of Lock C-1. Monitoring for the invasive is being conducted throughout the canal, the lake and the Richelieu River north of the lake.

“Early detection is extremely important in preventing the spread of a suspected new invasive species from entering our environment,” DEC interim Commissioner Sean Mahar said in a statement. 

Plans in place

Meg Modley, an invasive species specialist with the Lake Champlain Basin Program, said the response to the eDNA detection was a sign that the multi-agency prevention plan was working. She said the detection prompted additional monitoring in the water and more prevention in the canal system. 

“[DEC and the canal] have a round goby response plan in place and are already moving to take appropriate preventative measures,” Modley said. “It’s reducing the number of times or opportunities that goby would have to move upstream through the system.”

Round goby fish were captured near Troy in July 2022, raising concerns that the invasive species could make its way through the canal into Lake Champlain. The canal starts above the confluence of the Mohawk and Hudson rivers and runs inside the Hudson until breaking off the river near Fort Edward, crossing into the Champlain watershed and entering Champlain’s southern narrows near Whitehall.

About the round goby

Round goby is suspected to have made its way to the Great Lakes in shipping container ballast water around 1990. Within five years, the fish had invaded all of the Great Lakes. They have since spread through the Mohawk River and Erie Canal to the Hudson watershed. 

Prolific breeders, reproducing every 20 days during the hatching season, round goby feed on the eggs and fry of native fish while overtaking important habitat. They can also carry diseases capable of passing to other fish and birds.

“Any possible spread of the round goby is a concern for all of us and as we work closely with DEC and other partners to further investigate this preliminary detection, the Canal Corporation is taking immediate action to expand our mitigation efforts,” Canal Corporation Direction Brian Stratton said in a statement.