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Exotic Species Introductions into Lake Champlain:
the Role of Canals
J. Ellen Marsden, School of Natural Resources, University of Vermont
Michael Hauser, Vermont Department of Environmental Conservation
Mark Malchoff, Lake Champlain Sea Grant
THE PAST
THE PRESENT
Human activities in and around Lake Champlain since the arrival of settlers have led to
the deliberate and accidental introduction of exotic species, such as plants, snails, and
sport fishes. Beginning in the early 1800s, canals were built to connect Lake Champlain
with the Great Lakes, Mohawk River, and Hudson River. These canals increased the
transport of exotic species from and between neighboring watersheds. Lake Champlain
currently contains over 40 exotic species, including several nuisance species – sea
lamprey, zebra mussels, water milfoil, and water chestnut; at least 40% arrived in the lake
via canals.
THE FUTURE
Lake Champlain’s recreational value for anglers, boaters, swimmers, and beachgoers is
significantly impacted by exotic species. Native species are threatened by competition
with exotics: for example, native plants are often overwhelmed by invasions of fastgrowing non-natives, and restoration of lake trout and Atlantic salmon is threatened by
predation from sea lamprey.
The rate of exotic species introductions into Lake Champlain has increased over the past
several decades, and will likely continue; there are at least 10 exotic species in nearby
waterways that are poised to enter the lake. Several of these, including fishes (round goby,
ruffe), zooplankton (spiny water flea, fishhook flea), and molluscs (Asian clam, quagga
mussel) are likely to cause ecological and economic problems if introduced.
In 2002, 20% of muskellunge and
northern pike in the northern part
of the lake were infected with a
lympho-sarcoma, previously
unknown in the lake.
Vectors of exotic species introductions
St. Lawrence R.
Credit: USGS
Fish-hook flea (Cercopagis pengoi)
Ruffe (Gymnocephalus cernuus)
Credit: Wisconsin Sea Grant
Lake Champlain and its canals have also served as a conduit for invasions between other
previously isolated watersheds. An estimated 16 species have moved between the
Hudson River, Great Lakes, and St. Lawrence River drainages using the Champlain Canal
and Lake Champlain as an invasion route.
Credit: USFWS
Credit: Dept. of Fisheries and Oceans, Canada
Shipping
Richelieu River
Chambly
Canal - 1843
Vector
Bait
Credit: Bernie May
Escapes
Quagga mussel
Stocked
(Dreissena bugensis)
Credit: Great Lakes Fishery Commission
Unknown
Lake
Champlain
Source: www.foodsubs.com
Canals
0
5
10
15
20
Number of species
The majority of exotic species for which we
know the route of introduction entered the lake
via canals, built in the 1800s, that link Lake
Champlain with adjacent waterways. These
canals were built to facilitate shipping between
the Hudson River, St. Lawrence River, and Lake
Champlain, but provide an easy passage for
aquatic species.
Champlain
Canal - 1823
Hudson
River
Rusty crayfish and other exotic
crayfish compete with native
species and may damage aquatic
vegetation
Crustaceans
14%
Other
5%
Fish
29%
Sea lamprey prey on salmon and
trout, causing significant problems
for the fishery and species
restoration
Molluscs
25%
Can we halt the invasions?
Round goby (Neogobius
melanostomus)
To stop future invasions of the Lake Champlain basin, each of the potential vectors
needs to be managed. Progress is underway:
• Legislation to manage bait fish introductions in Vermont was passed in 2002
• Stocked fishes are managed by state agencies; new species are unlikely to be
added through normal fisheries management activities
• Accidental releases may be reduced by educating the public about the problems
due to exotic species
However, canal introductions represent a major source of exotic species
invasions. Our research, involving input from a wide variety of stakeholders, is
directed at finding an optimal barrier to exotic species transfer through the
Champlain Canal. Potential options include chemical, electrical, biological, or
physical barriers.
Plants
27%
Exotic species in Lake Champlain, by taxon
Timeline of exotic species introductions into Lake Champlain
14
10
year of arrival
year of first sighting
(arrival date unknown)
8
6
4
Country of origin
Number of species
Sources of exotic species in Lake Champlain
12
Eurasia
US
Atlantic coast
New Enland
2
Hudson/St. Lawrence
0
<1920 1920 1930 1940 1950 1960 1970 1980 1990 2000
Decade of arrival (or first sighting)
The rate of exotic species introductions into Lake
Champlain has been gradually increasing; four species
have entered the lake already since 2000. This trend has
also been noted in the Great Lakes, and may be related
to increased human activity in the basin.
0
5
10
15
20
25
30
Number of species
The majority of exotic species in Lake Champlain
originated from Europe and Asia; most of these species
were introduced elsewhere in the US before they
arrived into Lake Champlain
Credit: Mystic River Watershed Assoc.
Dense colonies of zebra mussels can kill native
mussels, alter aquatic food webs, and foul water
intake pipes and other underwater structures
Water chestnut, water milfoil, and a variety of
other aquatic plants can outcompete native
species and reduce habitat and food availability
for ducks, fish and wildlife. They also cause
severe problems for boaters and swimmers.
Lock 12 on the Champlain Canal – route of boaters,
kayakers, and exotic species into Lake Champlain
Acknowledgements: This study was funded by National Sea Grant under a special
appropriation; particular appreciation goes to Senator Patrick Leahy for his
recognition of the need for this work.
Photo credits: J. Ellen Marsden, unless otherwise noted