A little fish called the round goby has been spotted recently in the Hudson River near Poughkeepsie, and threatens to cause big problems for the river and other water bodies connected to it. This week, a state plan to keep the goby from spreading from the Hudson into Lake Champlain will be tested, when the canal that connects the lake and the river is reopened for the season. Ecologists are hoping the plan will work, but worried that it might not go far enough—and it might be New York’s only chance to keep the fish from wreaking further havoc upstream.
Native to the Black and Caspian Seas of Eurasia, the round goby was accidentally introduced to New York’s Great Lakes Ontario and Erie in the late 1990s, and has become aggressively invasive there, displacing native fish and changing local food webs. A small fish with a maximum length of 10 inches, the round goby can thrive in a wide variety of conditions and different levels of salinity, and is a prolific breeder. In the past decade, the round goby has increasingly spread further south and east along the state’s rivers and tributaries, traveling along the Erie Canal to reach the Hudson River. Recent sightings in the Hudson as far south as Poughkeepsie are a cause for great concern about the health of Hudson River ecosystems, according to local ecologists.
“The goby is a voracious eater,” says Dan Shapley, co-director of the Science and Patrol Program at Riverkeeper. “It loves to eat eggs, so it’s going to consume the eggs of many of our native species. Many of our native species are already in decline, at risk, or barely showing signs of recovery from historic overfishing, habitat loss, or pollution.”
Like other invasive species, the round goby is adept at thriving and proliferating in unfamiliar environments. The introduction of the goby into local waterways will have ripple effects throughout the larger ecosystem, but ecologists can’t predict exactly what the impacts will be.
One wild card: The round goby eats zebra mussels, which are also an invasive species in the Great Lakes and the Hudson River. The goby might reduce zebra mussel populations, but in the Great Lakes, round gobies feeding on mussels has caused certain toxins found in mussels, such as botulism toxin, to be concentrated and move up the food chain. In the Great Lakes, thousands of waterbirds who eat gobies have died from ingesting botulism toxin and other pollutants. Ecologists can’t be sure if this will happen in the Hudson River, but given its large population of zebra mussels, it’s a risk.
Another unknown question is whether the spread of the round goby will have a negative effect on the Atlantic sturgeon, an iconic Hudson River fish that has made something of a comeback in the Hudson and other American waterways in recent years, after being fished almost to extinction. “Will gobies benefit the Hudson’s sturgeons (Great Lakes sturgeons treat gobies as choice prey)? Or will they eat so many sturgeon eggs that they reverse the recent recovery of these endangered fish in the Hudson?” ecologist David Strayer, of the Cary Institute in Millbrook, wrote in a 2021 blog post.
Once an invasive species establishes itself somewhere, there’s not much that can be done except monitor and study its impact. “Once it’s here, it’s here,” Shapley says. “Sometimes you can manage it. Sometimes you can limit the impacts, but in general, it’s here and it’s unavoidable.”
With the round goby already on the march down the Hudson, conservationists are now directing their attention to preventing the fish from entering Lake Champlain. The Champlain Canal provides a clear artificial passage from the Hudson River to Lake Champlain, a potential route for the round goby. On May 20, the canal reopens for the season after being closed since last October.
Since the discovery of the round goby in the Hudson River, the Nature Conservancy has been pushing state officials to implement plans to protect Lake Champlain by closing the locks that control boat travel along the canal. “We really mobilized knowing that it was discovered in the Hudson,” says Peg Olsen, the Adirondack director of the Nature Conservancy in New York. “Then the canal was closed for the winter. Knowing that it’s going to reopen May 20th, we really felt there was this small window of time to mobilize and make the case again to DEC, the Canal Corporation, and the governor, to close just one of those locks to prevent the goby from getting into Lake Champlain.”
In March, the New York State Department of Environmental Conservation and the Canal Corporation that manages the state’s canals and locks released their plan to prevent the goby from invading the lake. The plan involves tracking and monitoring the travel of the round goby, implementing “double draining” of specific locks of the Champlain Canal, developing electric field barriers and other forms of technology to physically restrict upstream migration, launching a public education campaign, and evaluating the potential economic and ecological effects of the round goby. But the plan falls short of what the Nature Conservancy has been urging: The DEC’s plan does not involve closing any of the locks once they’re set to reopen for the season on May 20th.
“The ultimate goal is, the [federal] Army Corps and others are working on developing a barrier system,” Olsen says. “When we are calling for the closing of a lock, we’re talking about a temporary closing until that system is developed. We’re saying, ‘Look, we have an opportunity here to prevent it from getting in while we’re coming up with the permanent solution.’”
Still, the DEC is hesitant to close any of the canal locks, even temporarily. While there is very little commercial use of the Champlain Canal these days, the canal is still a route for a small amount of boat traffic. “The heyday of the canal system being for commercial transportation is really over. It’s recreational boating for the most part, and even those numbers of boats that go through are very low,” Olsen says. “But we do recognize that there’s a culture around the canal system, that’s valued by a group of people. But again, it’s asking for a temporary closure where you could still have a boat lift for boats that wanted to go through.”
The DEC taking action on the problem is welcome, Olsen says, but she worries that the plan may not be strong enough to prevent the goby from invading Lake Champlain. “While we’re obviously pleased that there’s been recognition of the problem, and some call to action, we still believe the words of Ben Franklin: ‘An ounce of prevention is worth a pound of cure.’ And in this case, it’s closing just one lock.”