Healthy ecosystems provide habitat for native species, retain nutrients and sediment, and store floodwaters. Efforts to protect critical habitat in the Lake Champlain Basin, such as riparian and wetland areas, include improving habitat connectivity and wildlife passage, reducing nutrient runoff into rivers and streams, supporting restoration measures for species of concern, and reducing the risk of new invasions of non-native species.

FISH HEALTH

Anglers find that fishing in Lake Champlain is good in every season, whether fishing for walleye, pike, bass, Atlantic salmon, lake trout, or perch. 

The Lake is home to more than 80 species of fish, including key sport fish species that attract fishing tournaments of all sizes, from local fishing club derbies to large national competitions. In 2016 and 2017, anglers caught state record-sized carp, cisco, freshwater drum, and redhorse sucker in Lake Champlain and its tributaries.

Lake trout, Atlantic salmon, and other high-priority game fish species continue to be stocked in Lake Champlain by state and federal fish and wildlife agencies in Vermont and New York to support the Lake Champlain sport fishery. In the summer of 2017, the U.S. Fish and Wildlife Service (USFWS) celebrated the reopening of the White River National Fish Hatchery in Bethel, Vermont. The hatchery, which was severely damaged by Tropical Storm Irene in 2011 and subsequently decommissioned, is once again an important source of broodstock of Atlantic salmon and lake trout for the Lake Champlain Basin.

The 40-year effort to restore lake trout in Lake Champlain has shown recent promise. Scientists from the University of Vermont have found that the percentage of wild juvenile lake trout in Lake Champlain (the offspring of stocked fish) increased from 24% of lake trout collected in 2015 to nearly 50% in 2017. The surge is likely a result of changes in the diet of recently hatched trout, reduction in predation, improved sea lamprey control, and changes in the use of spawning sites.

Non-native and invasive fish species continue to be a challenge in Lake Champlain. Populations of alewife, tench, rudd, and some of the more popular introduced species, such as rainbow and brown trout, have increased in number and size. Invasive alewife continue to disrupt the Lake Champlain food chain by outcompeting and displacing native rainbow smelt, the primary food source for lake trout and Atlantic salmon. Some sport fish will prey on alewife, but a diet rich in alewife can lead to elevated ingestion of the enzyme thiaminase in lake trout and Atlantic salmon. This enzyme can prevent the uptake of thiamine in some salmonid eggs, leading to early mortality in hatchlings.

Atlantic salmon

The U.S. Fish and Wildlife Service and its partners work to ensure that anglers enjoy a healthy fishery in Lake Champlain. Photo: USFWS.

The wounding rate of Atlantic salmon by sea lamprey is near target limits established by fisheries managers, though challenges remain for lake trout.

Sea lamprey are eel-like parasitic fish that have had devastating impacts on Atlantic salmon, lake trout, and other sport fish in Lake Champlain. The fish are native to the Atlantic Ocean, and debate continues as to whether they are a native nuisance or an invasive species in Lake Champlain. Sea lamprey spend the first four years of their lives as larvae in tributaries to the Lake. In their fifth year, most lamprey become parasitic and enter the Lake, where they attach to host fish and feed on the host’s blood and body fluids.

A long-term management program, operated since 2002 by the Lake Champlain Fish and Wildlife Management Cooperative in partnership with Vermont Fish and Wildlife Department and New York State Department of Environmental Conservation, has helped to reduce sea lamprey impacts on native fish. In this collaborative effort, researchers prioritize and treat tributaries by evaluating lamprey larval density in rivers, streams, and deltas; monitor trends in lamprey populations; and study the effectiveness of chemical treatments. Methods of control include installing barriers to prevent spawning, using traps, and applying chemical pesticides called lampricides in rivers and deltas. These efforts have had some success. A seasonally-operated barrier on the Morpion Stream in Québec, for example, has eliminated reproduction in upstream sections. And the first-time use of lampricide in the LaPlatte River in Shelburne, Vermont, has reduced a previously uncontrolled source of sea lamprey.

All of these methods are designed to have their effect during the sea lamprey’s larval stage, before they become parasitic and prey on fish in Lake Champlain. The ultimate goal is to reduce the amount of chemicals required to control the species, but in the meantime, the USFWS ensures that treatments have limited impacts on non-target species, especially threatened and endangered species. Lake sturgeon, channel and eastern sand darters, stonecats, mudpuppies, mussels, and native lamprey species may be susceptible to lampricides. Lampricides are non-toxic to humans and mammals at the levels in which they are applied in the Lake Champlain Basin. However, residents within treatment areas are notified before treatment occurs and advised of a temporary limit on fishing and recreation and on using water for human consumption, domestic use, irrigation, or livestock watering.

Figure 10 - Sea lamprey wounding rates in Lake Champlain, 2002-2017

Figure 10 | Sea lamprey wounding rates in Lake Champlain, 2002-2017

In the last few years, the number of sea lamprey wounds observed on Atlantic salmon has remained near the established limit, while the wounding rate of lake trout has increased (Figure 10). A number of factors may affect wounding rates, including sample collection and reproduction success of both lamprey and salmonids.