Weeding Out Unwanted Visitors
John Garver is a professor of geology at Union College who also does research and advocacy work surrounding the Mohawk River and Erie Canal. Garver is holding up an aquatic invasive plant, the water chestnut. The water chestnut grows quickly, forming a mat across the water, and one method of removal is through hand pulling plants out of the canal. Photo courtesy of Jacqueline A Smith.
Ed Skorupski’s boat came to a stop. He was already going slow, but the thick mat of plants surrounding his aluminum fishing boat caused him to have to clean his propeller before continuing forward. Currently enjoying his retirement, Skorupski spends a majority of his free time fishing the Champlain Canal.
It was more than likely that Skorupski was slowed down by water chestnuts. They are just one of the many aquatic invasive plants in the New York canal network. Aquatic invasive plants exist in bodies of water that they are not native to and have the potential to spread rapidly.
When the plants become overgrown and form mats at the water's surface, they block sunlight, killing native plant species. By limiting the diversity of the plant community, invasive species have a rolling effect on the habitat where other native species eat or reproduce. The combination of invasive and native plant life will end up decreasing the oxygen levels in the water, which can potentially damage or kill off fish populations. These mats also have an impact on people who use the water recreationally.
Navigating invasive species is nothing new to Skorupski. He has experienced heavy aquatic plants, but nothing to the point where he can’t get his boat through. Skorupski simply lifts his motor up, untangles the weeds, and continues on his way. When it came time to exit the lake, he needed to wash his boat down to prevent the transportation of aquatic invasive plants. Depending on where he’s fished, Skorupski might go through a cleaning station. If there is not one, he said a carwash works just as well.
“You don’t want to pull your boat out and have plants entangled in the carriage and then drive an hour to the next lake and not clean it off,” Skorpuski said. “That’s the primary means by which aquatic plants have been transferred from one water body to another.”
Had Skorpuski traveled a little further down the Champlain Canal toward the Hudson River, he could have passed into the Erie Canal. The spots where canals connect are important management areas for preventing the spread of aquatic invasive species. If a boat enters into a different area without first being properly cleaned off, it risks bringing aquatic invasive species into that next body of water. The instant invasive species move from one region to the next, they begin to occupy that space and damage the native species.
"The resources that attract people to the canal – its water quality and the ability to fish – are at risk if invasive species are not addressed."
This is what happened with the aquatic invasive plant water chestnuts as they spread from the Erie Canal into the Champlain Canal. The water chestnut is largely an issue on the lower part of the Mohawk River, the very beginning of the Erie Canal. It entered at the southern end of Lake Champlain through the Champlain Canal in the 1940s, according to Meg Modley, the aquatic invasive species management coordinator for the Lake Champlain Basin program. She said that the greatest number of known invaders to Lake Champlain have come through the canal system. When this occurs, Modley said it is very important they are managed right away.
“If you’re talking about the water chestnut, that’s a floating annual plant,” said Modley. “That clogs waterways, that chokes up marinas, that reduces oxygen levels in the water.”
Annual plants die after one growing season. But water chestnuts grow about 15 to 20 seeds per plant, and these seeds can fall from the plant and travel through the water. This means the best prevention is to remove the plant before seeds have formed.
An aquatic invasive plant Modley is thankful has not reached Lake Champlain from the Erie Canal is hydrilla.
Hydrilla is described as one of the most invasive aquatic plants currently being observed. It is currently in the Finger Lakes, and there is growing worry that it will spread to the rest of the canal. Hydrilla has been intercepted on boats and trailers through the Lake Champlain Basin program’s watercraft inspection decontamination program. It has the ability to grow up to an inch a day, and once it reaches the surface, will continue to grow horizontally across the water, creating thick mats.
John Garver, professor of geology at Union College, works on the issues surrounding the Mohawk River, and said the potential spread of the hydrilla is a recipe for absolute disaster.
“It will be able to take route and take over and literally choke out the entire canal,” Garver said. “People try to kayak through it and they can’t. People try to boat through it, they get their engines clogged with a bunch of this stuff. It has tangible effects on the recreational use of the Erie Canal system.”
In order to keep the waters navigable, experts like Garver said anyone who uses the canal should actively check that they are not transferring invasive species by following the steps clean, drain and dry. This includes rinsing the equipment, interior and motor of any visible aquatic species or mud, draining any devices that contain water, and drying everything for at least five days or using a towel.
The presence of hydrilla in the Erie Canal highlights the importance of prevention of aquatic invasive species, said Sam Beck-Andersen, associate director of invasive species programs at the Finger Lakes Institute (FLI) and coordinator at Finger Lakes Partnership for Regional Invasive Species Management (PRISM). FLI and PRISM oversee the Watercraft Steward Program in which stewards are placed at some of the busiest boat launch points in New York state. They inspect boats and educate boaters about the “Clean, Drain and Dry” process. Beck-Andersen said hydrilla is at the top of their list for prevention and management. By monitoring where it is, he and his team can prevent hydrilla from leaving that spot.
“It’s so low abundance in that area where we can theoretically keep it away from certain locations because it isn’t super widespread,” Beck-Andersen said. “Prevention becomes even more important and more focused.”
Garver said the resources that attract people to the canal — its water quality and the ability to fish — are at risk if invasive species are not addressed.
“I think almost everybody who uses the canal uses it because they want to fish, they want to look at birds, they want to enjoy nature,” said Garver. “And if that’s gone, then we’ve really blown it.”
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