Lake Champlain Summary

adapted from Vermont Fish and Wildlife Wildlife Action Plans

Lake Champlain includes the main body of the lake and its bays and river deltas. These waters are shared with New York and Quebec. At about 120 miles in length and a maximum depth over 400 feet, this is Vermont’s largest waterbody. Aquatic habitats found here are many and extensive. Among these are expansive sand-bottomed shallows, shale/cobble littoral shorelines and bays, and deep limnetic environments. Other natural communities, such as large tributaries, emergent marshes, and floodplain forests, are integral to Lake Champlain and provide a critical habitat component for many SGCN found here. This is, in general, an oligo-mesotrophic lake, with nutrient levels in different parts of the lake dependent on local soil and bedrock types, as well as the type and extent of human land use within the surrounding watershed. This lake supports the highest lacustrine diversity of any of our lakes, which is due mainly to its large size and connections (current and historical) with the Great Lakes-St. Lawrence River and the Hudson River.

Lake Champlain Condition

Current Condition: The most outstanding concerns facing this large system are water quality and habitat degradation, and invasive exotic species. The lake is within the largest watershed in Vermont and is fed by many large tributaries that drain extensive agricultural and developed lands. A significant portion of the excessive nutrients, contaminants, and fine sediments that enter streams and rivers eventually reach Lake Champlain. Water and benthic habitat quality are affected, particularly in delta areas and along the shoreline, but also within the open and deeper waters over time. SGCN that are sensitive to contaminants and those that depend on consolidated (firmly-packed) substrates may be impacted by these changes to their habitat. Development along Lake Champlain’s shoreline and within smaller watersheds immediate to the lake is ever-increasing, and with it the amount of contaminants entering directly into the lake. Excessive nutrients that reach the lake from various land uses within the watershed can cause eutrophication, reducing water quality and altering food webs. Zebra mussels have had a dramatic and devastating impact on the biotic community of Lake Champlain, including populations of many SGCN. These exotic pests foul the shells of native freshwater mussels, decreasing their ability to move about and obtain food and oxygen, resulting in a slow death. Populations of native mussels have been eliminated from large areas, a scenario that has repeated itself throughout most of the lake. The only areas where native mussels have not been seriously impacted by zebra mussels are Mallets Bay, the Inland Sea, and Missisquoi Bay. Water chestnut is an invasive that has impacted aquatic communities in the lake by forming huge, dense masses that cover the water surface and crowd out species. The exotic snail Bithynia tentaculata now dominates much of the shale/cobble habitat in Lake Champlain, likely reducing native snail populations and altering the food web. Among other invasive exotics that loom on the horizon for Lake Champlain are round goby, alewife, quagga mussel, and rusty crayfish. Additional problems to Lake Champlain include habitat conversion and vulnerability to catastrophic contaminant spills.

Desired Condition (SGCN Needs): These waters, along with Lake Champlain tributaries, support the greatest diversity of aquatic species found in the state. SGCN supported by Lake Champlain include mid- to deep-water species like cisco and lake whitefish that require cold, well-oxygenated waters. Shallow-water species such as mooneye and sauger utilize upper portions of the lake where temperatures are often much warmer. Near-shore and benthic species like bridle shiner, pink heelsplitter, giant floater, and spiny softshell are often found in bays or in the shallows of deltas.

The lake offers a variety of habitats that provide for the many needs of aquatic species, such as refuge, food, thermal protection, and spawning substrate. The great majority of freshwater mussel species remain buried in the substrate most of their lives, where they grow, feed, produce offspring, and seek refuge from the elements. Lake sturgeon feed on lake-bottom invertebrates, only entering rivers for brief periods to spawn. Different fishes can be found occupying different strata of the lake where they find the temperatures and oxygen levels they prefer. Degradation of water quality through nutrient input, thermal shifts, or other changes can cause significant alterations in food webs and habitat availability. Similarly, excessive fine sediments entering the lake from the shoreline and tributaries blankets and degrades the benthic substrate used by many SGCN. Improvement and protection of Lake Champlain’s water quality, including reduction of nutrient and fine sediment inputs, is paramount to ensure that the SGCN populations found here remain viable. Control of exotic species, including preventing new species from invading, is also of great importance to the survival of these native species.

Many SGCN utilizing Lake Champlain depend on closely associated aquatic, wetland, and terrestrial habitats to complete their life cycles. Many fish, such as lake sturgeon, greater redhorse, and mooneye are found in the lake most of the year, but spawn over rocky substrates in Champlain tributaries. Osprey feed in the lake but need nearby suitable nesting trees or structures to raise their young. Spiny softshells occupy the lake much of the year for basking, feeding, and over-wintering, but require adjacent beaches of sand or gravel/cobble for egg-laying. Bats feed on emerging aquatic insects over the lake, while utilizing upland roosting and nursery sites. Muskrats river otter and mink find a rich aquatic food source within Lake Champlain and its associated wetlands, but must den above the waterline. Maintaining these connections to critical wetland, aquatic, and terrestrial habitat is key to ensuring the continuation of these SGCN in the lake.

Species of Greatest Conservation Need in Lake Champlain

High Priority

American Brook Lamprey (Lampetra appendix)
Lake Sturgeon (Acipenser fulvescens)
American Eel (Anguilla rostrata)
Muskellunge (Esox masquinongy)
Silver Redhorse (Moxostoma anisurum)
Greater Redhorse (Moxostoma valenciennesi)
Quillback (Carpiodes cyprinus)
Sauger (Sander canadense)
Blackchin Shiner (Notropis heterodon)
Bridle Shiner (Notropis bifrenatus)
Crustaceans Group
Freshwater Mussels Group
Freshwater Snails group  

Medium Priority

Cisco or Lake Herring (Coregonus artedi)
Lake Whitefish (Coregonus clupeaformis)
Mooneye (Hiodon tergisus)
Silver Lamprey (Ichthyomyzon unicuspis)
Shorthead Redhorse (Moxostoma macrolepidotum)
Atlantic Salmon (landlocked) (Salmo salar)
Lake Trout (naturally reproducing populations) (Salvelinus namaycush) 

SGCN Note: SGCN plants not listed here 7 species. The SGCN invertebrate groups listed here contain numerous species.  Sea lamprey is not a Species of Greatest Conservation Need in the Lake Champlain Basin. For more information about a specific Species of Greatest Conservation Need see that species' assessment summary in Appendix A.