 Canada's many freshwater lakes and streams are home to rainbow trout, Arctic char, and brook trout.In the past, invasive species such as the lamprey and zebra mussel have threatened these native species, and while efforts to combat them have been made they still remain a hazard in some areas, and there are ongoing effort to prevent the spread of Asian carp from the United States.There are also significant commercial fisheries of many salt-water species, including Atlantic cod, haddock and halibut, although some of these are in decline.