Invasive Species

Species that are non-native to Lake Champlain and likely to cause ecological or environmental harm are considered "invasive." The Lake Champlain Committee works to prevent the establishment and spread of aquatic and semi-aquatic invasive species in Lake Champlain and its basin. In the absence of ecological controls such as disease and predators, non-native species can out-compete natives, which depletes the lake's native bio-diversity. 

Once established, species are impossible to eradicate. Zebra mussels entered Lake Champlain around 1993 and have proliferated, smothering native mussel species, coating water intake pipes, and slicing the feet of unsuspecting swimmers. 

Alewives were first found in the lake in 2003 and have since become a dominant forage fish. Recent winter kills of alewives have led to tons of rotting fish washing ashore after the ice has melted, but they do not seem to have impacted the lakewide population of that fish.

Eurasian watermilfoil has spread throughout the lake, creating a challenge and nuisance for swimmers and boaters. The closely related variable-leaved milfoil was discovered in Missisquoi Bay and in the South Lake since 2009.

In addition to invasive species, native species can sometimes become out of balance with the ecosystem. For example, sea lamprey are a native species whose populations are currently high enough to threaten the long-term wellbeing of other native species. The Lake Champlain Committee has worked to identify and develop means of controlling sea lamprey that minimize the use of pesticides.

How did they get here?

Of the exotic species whose origin of introduction to Lake Champlain is known, more than 60 percent entered via canals, particularly the Champlain Canal at the southern end of the lake.  Many more species stand poised to join them.  The Hudson River has over twice as many exotic species as Lake Champlain; the Great Lakes host nearly four times more.

Species on the horizon

Round goby. Photo from wikipedia.org

A horde of invasive species moves closer to Lake Champlain, ready to invade its waters. The following species are currently on the hot list, and the Lake Champlain Committee is working to reduce the chance that they will be successful.

Round goby: a fish species native to the Caspian and Black Sea regions. They were introduced to the Great Lakes probably from a ship's discharged ballast water, and first found in North America in 1990 in the St. Clair River. Gobies are bottom-dwelling fish that perch on rocks and substrate. They grow up to 10 inches long and have large heads, soft bodies and dorsal fins that lack spines. Often confused with sculpins, the round goby is distinguished by its fused pelvic (bottom) fin which forms a suction disk that allows them to anchor to the bottom. No fish native to North America has this feature.

Round gobies are predators of many native fish such as darters, sculpins, and logperch. Populations of some of these species have seen substantial declines in the St. Clair River. They also eat eggs and fry of lake trout and eggs of lake sturgeon. They have been implicated in major die-offs of birds in the Great Lakes. They can harbor the bacterium that causes avian botulism; this is transmitted to the birds that eat round gobies.

Hydrilla on a boat engine. Photo: Louisiana Sea Grant College Program

Hydrilla: a highly aggressive plant. Hydrilla has clogged drainage canals in the southeast and populations have been reported as close as Massachusetts, Maine, and Suffolk and Orange Counties in New York. A strain of hydrilla was found in the north in the Potomac Basin in the 1980s. Fragments falling from boats, trailers, and live wells can start new populations, which often begin near boat launches. Compared to other aquatic plants, hydrilla grows well in deeper, darker waters and new infestations may establish a foothold there before spreading into shallower waters and out-competing other resident plants.

Symptoms of VHS on a gizzard shad. Photo: USFWS

VHS: viral hemorrhagic septicemia – an often lethal disease of fish that affects numerous species. The presence of VHS in the Great Lakes drainage has led to imposition of significant restrictions on transport of fish between waterbodies. VHS is such a significant disease that new outbreaks have to be reported to the World Health Organization for Animal Health. The disease transmits easily between fish (both individuals and species) and mortality seems to be highest in colder waters (37-54 oF). Some fish may be carriers of the virus and exhibit no external signs. The actual presence of the disease can only be determined by laboratory testing.

Fishhook waterflea (top) and spiny waterflea (bottom). Photo J. Liebig NOAA GLERL

Spiny water flea and fishhook water flea:  two plankton species that could dramatically disrupt Lake Champlain’s food web. Spiny water flea and fishhook water flea both came from Northeast Europe. The spiny water flea was first noted in Lake Huron in 1984 and the fishhook water flea in Lake Ontario in 1998. Both most likely were released with a ship's ballast water. In addition to competing with native zooplankton, spiny water flea and fishhook water flea are much more difficult for small fish to ingest, thus a poorer food source. The long spines of these species can hook them onto anglers’ lines in the hundreds, making fishing difficult. In the summer of 2012 the spiny water flea was found in the Champlain Canal and in Lake George. Both have hydrologic connections to Lake Champlain. Eggs and adult water fleas can travel unseen in a boat's bilge water, bait buckets, and live wells.

LCC's Past and Ongoing Projects

  • Worked to secure ongoing funding for control of water chestnut populations.
  • Member Lake Champlain Basin Aquatic Nuisance Species Task Force, developing management plans for the basin's invasive species.
  • Member US Fish and Wildlife Service Alternative Sea Lamprey Control Task Force seeking innovations to limit the amount of pesticide needed to control sea lamprey in Lake Champlain.
  • Helped develop a plan for rapidly responding to new invaders as they arrive and are discovered.
  • Provide educational materials to help citizens stop invasive species. 
  • Successfully advocated for regulations and fines to make the transport of invasive species a crime. 
  • Promoted baitfish regulations to minimize invasive species introductions. 
  • Led efforts to initiate the rapid response plan when Asian clams were discovered in the Champlain Canal.
  • Undertook vegetation surveys in Missisquoi Bay and the Northeast Arm to assess the prevalence of invasive species and conduct rapid response against any new populations found.
  • Called for closing a portion of the Champlain Canal to prevent the spread of invasive species into Lake Champlain.