How are the populations of Lake
Champlain's sport fish changing?
Greater numbers of larger and healthier sport fish have been caught in recent years on Lake Champlain, compared to the 1980s and ’90s, and there has been a reduction in the frequency of sea lamprey wounds. Atlantic salmon runs in Lake Champlain tributaries continue to increase each year. Weigh-ins at bass tournaments for several years have demonstrated a strong and healthy bass fishery in the Lake.
Lake Champlain is home to over 80 species of fish and is known particularly for its salmonid, bass, and walleye fisheries. Fishing tournaments on Lake Champlain have increased in number and popularity, ranging from local fishing club tournaments and derbies to professional fishing competitions. Anglers visiting Lake Champlain come from all over the country to participate in these competitions and to enjoy fishing on the Lake. Although solid ice coverage across the Lake is now less frequent than in previous decades, winter weather always brings ice to the bays and near-shore areas that are more protected from the wind, providing good ice fishing.
Non-native fish species in Lake Champlain have increased in number over the last decade, and include alewife, tench, white perch and rudd, as well as some of the more popular introduced species such as rainbow and brown trout. Some of these species (alewife in particular) are problematic, outcompeting native forage fish that have traditionally comprised the diet of fishes higher up the food chain, including our most popular sport fishes. As trout and salmon start to rely more on alewife as a food source, they ingest greater quantities of the enzyme thiaminase, which has been shown in other lakes to cause a thiamine deficiency in eggs and fry, known as Early Mortality Syndrome. Since the arrival of alewife in Lake Champlain, salmonid eggs from the Lake that are used for rearing hatchery fish are checked annually for possible thiamine deficiency and are treated with a thiamine supplement.
Several species of fish continue to be stocked regularly into Lake Champlain, including lake trout and Atlantic salmon. This fish cultivation and stocking program is especially important because natural lake trout and Atlantic salmon do not currently have enough reproductive success to sustain their Lake Champlain populations. Researchers are investigating causes of poor survival of young salmonids, and are monitoring movement of these species throughout the Lake to better inform restoration efforts.