Uninvited: The Round Goby
Invasive fish species threatens Lake Champlain
Meet the Round Goby
The round goby (Neogobius melanostomus) is one of the greatest threats to the Lake Champlain ecosystem today. This invasive fish has steadily made its way closer to Lake Champlain since it was introduced to the Great Lakes from Eurasia in the early 1990s. If it reaches Lake Champlain, it could decimate the Lake’s fishery. What is an aquatic invasive species? >>
Scientists and agencies that work to protect the health of the Lake have made preventing the introduction of round goby one of their greatest priorities.
The round goby is a bottom-dwelling fish that is brownish gray with brown or black splotches. Key features of this species are a dark black spot on the first dorsal fin and a single fused pelvic fin. They have large, raised eyes that are frog-like in appearance. They range in size from 4-10 inches in length.
The round goby is salt-tolerant, meaning it can live in both fresh and salt water. It lives on the bottom of lakes and rivers where the water is shallow, typically below 60 meters. They prefer water bodies with a rocky, sandy, or gravelly bottom.
The round goby is native to the Black and Caspian Seas in Central Eurasia, where they coexist in balance with other native species. This region is home to many other species, including the zebra mussel and quagga mussel, that are invasive in North America.
Round Goby Look-A-Likes
Here in North America, the round goby looks similar to native fish known as sculpins. In the Lake Champlain Basin, the mottled and slimy sculpin are native species and are eaten by larger fish like trout, pike, and bass.
The invasive round goby can be distinguished from native sculpin by looking at the pelvic fin. On a round goby, this fin is fused into one suction-cup-like fin, whereas sculpin have two distinct pelvic fins. A quick look at the bottom of the fish can help you confirm whether you're looking at a goby or a sculpin.
Use the slide feature in the middle of the photo to see the difference in pelvic fins.
Why are they a problem?
Like many invasive species, round goby did not evolve with species native to North American freshwater ecosystems. For this reason, their presence disrupts the natural food chain, alters habitat, and impacts the entire ecosystem.
Round goby are aggressive fish that eat a variety of native species including smaller fish, fish eggs and fry, aquatic insects, and bivalves like mussels. In fact, they evolved with the invasive zebra mussel, which is a readily available food source in Lake Champlain. Round gobies are both nocturnal and diurnal, which allows them to feed any time of the day or night.
Round goby have an incredible sensory system that enables them to feel small movements, making them efficient hunters in dark or cloudy waters. Because they have abundant food sources available to them, they are able to breed several times a season, which intensifies their impact throughout the food chain.
Do Gobies Consume the "Bottom Fry" Stage of Angled Smallmouth Bass? Video courtesy of Freshwater Fisheries Conservation Lab, Queen’s University, tuftslab.ca
Specific Impacts
- Compete directly with native fish like mottled sculpin, darter, and logperch for habitat and food
- Eat native mussels, native fish eggs, young fish, and many invertebrates that native fish species rely on for food
- Are associated with outbreaks of botulism which cause fish kills and annual die-offs of diving birds
- Act as a vector for viral hemorrhagic septicemia (VHS) a deadly fish virus that can be spread by moving fish from one body of water to another
- Accumulate mercury in their bodies which is passed on through predation to larger fish, fish-eating mammals, and birds
- Impact communities that benefit from recreational fishing and tourism
How did they get here?
The Black Sea is part of multiple important shipping routes linking eastern European countries to the entire world. As a hub of global trade with many busy ports, it has become a hotspot for invasive species transport. Species from around the world impact its fragile ecosystem, and it is a significant source of threats to other areas.
Over the past 30 years, ships have transported the round goby along with cargo to parts of Europe, the Baltic Sea, and the North American Great Lakes, where they have become invasive.
Like other invasive species, round goby was accidentally introduced to North America through ballast water of large ocean-going vessels coming from Europe. Ballast water is freshwater or saltwater held inside a ship to provide stability and maneuverability. It also provides additional weight for a ship to sit lower in the water to pass under bridges and other structures.
Ballast water transporting potential invasive species
Ships take on and release ballast water at several stages of a voyage and may do so at multiple ports. When ballast water is released, it may contain non-native organisms, both plant and animal, that could become invasive to that new watershed.
Making Way Through the Great Lakes
The round goby found its way to the Great Lakes in the early 1990s via Saint Clair River north of Windsor, Ontario. By 2010 it had spread throughout the Great Lakes and into the St. Lawrence River. It has continued to spread to other bodies of water including the Erie Canal, the Mohawk River, and the Hudson River.
The pathways for the spread include, natural movement along connected rivers and canals, bait buckets, and transport in water containment compartments in boats.
The map to the right shows the spread of Round Goby from 1990 through 2022. Click on the arrow to show an animation of the goby's spread. Data source: Non-indigenous Aquatic Species Data, USGS
On Lake Champlain's Doorstep
Scientists from the U.S. Geological Survey (USGS) captured round gobies in the Hudson River for the first time in summer 2021 near the confluence with the Mohawk River. The find marks the eastern-most extent of the expansion of this invasive fish from the Great Lakes through the Erie Canal, and another step closer to Lake Champlain’s doorstep.
Since then, scientists have documented round goby in the Hudson River downstream of Albany and upstream as far as Lock 1 of the Champlain Canal.
As of Spring 2023, round goby has not been found in Lake Champlain, in the Champlain Canal north (upstream) of Lock 1 near Troy, NY in the Hudson River, or in the Richelieu River south (upstream) of the St. Ours Dam (close to the St. Lawrence River).
How are they being monitored?
Preventing round goby from entering new waterbodies is difficult. Options include using traps, dams, closing canal locks, and using electrical or earthen barriers. Once round goby is established within a waterbody it is difficult to remove them without negatively affecting other species of fish.
Scientists from the United States Geological Survey (USGS), U.S. Fish and Wildlife Survive (USFWS), and the Québec Ministry of Forests, Wildlife and Parks (QC MFFP) conduct intensive monitoring during the summer months in the Hudson and Richelieu Rivers and in Lake Champlain. Monitoring consists of collecting water samples at various sites and then analyzing the samples for round goby DNA. Physical specimens are also collected when possible.
The New York State Power Authority/Canal Corporation is “double flushing” locks C1 and C2 along the Champlain Canal to reduce the likelihood that round goby will spread through the lock system as boats pass through. They also are practicing scheduled lockings to reduce the number of daily lockages or when round goby might challenge the lock system.
The NYS Power Authority/Canal Corporation and New York State Department of Environmental Conservation with input from the Lake Champlain AIS Rapid Response Task Force have drafted a Round Goby Rapid Response plan for the Champlain Canal. This plan outlines actions to be taken under certain scenarios, based on detection or confirmation of round goby at various locations within the Champlain Canal.
The plan is currently available here .
Right: LCBP staff and partners sample for Round Goby in the Hudson River during the fall of 2023. Electroshocks temporarily stun fish, which are then collected using dip nets and identified. Photo: LCBP
What Is An Aquatic Invasive Species?
Aquatic invasive species (AIS) are plants, animals, and pathogens (microscopic organisms that cause disease) that are non-native to an area and have been proven to cause harm to the economy, environment, or human health.
Number of aquatic invasive species present in connected waterways from the Great Lakes to Lake Champlain.
Lake Champlain is home to 51 known aquatic non-native and invasive species. Nearby waterbodies, including the St. Lawrence River, Great Lakes, and the Hudson River continue to pose AIS threats to Lake Champlain. These waterbodies are all connected to Lake Champlain by human-made canals. The Champlain Canal is the pathway by which the greatest number of known invasive species, including zebra mussels, water chestnut and white perch, have entered Lake Champlain.
Invasive species can adapt easily to a new location and outcompete native species through rapid reproduction and competition for food and other resources. They can cause millions of dollars of damage by clogging water intake pipes and encrusting critical infrastructure. They can also impair recreational uses of a waterbody, such as boating, swimming, and fishing.
What can I do?
If you fish, boat, swim or enjoy Lake Champlain, you can share in the caretaking of this beautiful waterbody. Here are some tips for what you can do:
Lake Champlain boater cleaning his boat and trailer to prevent the spread of aquatic invasive species.
- Practice clean, drain, and dry when transporting your boat from one waterbody to another. This includes checking your vehicle and trailer.
- Use bait that is native and disease free. Always empty your bait bucket on land. Never release live bait into a body of water.
- Learn how to identify round goby and report any encounters to your state Department of Environmental Conservation. Get photos on a dark background. Consider using smartphone apps like iMapInvasives or iNaturalist to capture your reports.
Explore Other Resources
- AIS in Lake Champlain ~ Lake Champlain Basin Program
- AIS Threats from Outside ~ Lake Champlain Basin Program
- AIS Spread Prevention ~ Lake Champlain Basin Program
- Champlain Canal Aquatic Invasive Species Barrier Study Phase I Report
- Hudson River Aquatic Invasive Species Task Force
- Aquatic Invasive Species In the Freshwater Section of the Saint Lawrence River
- USGS: Round Goby
- Champlain doing just fine without gobies (Bassmaster Conservation News)
