Lake Fish Health - Cape Breton Highlands

What? Lake fish health is being monitored in five lakes throughout Cape Breton Highlands National Park (Freshwater Lake, Warren Lake, Broad Cove Mountain Lake, Branch Pond, and Benjie’s Lake). Data collected is used to determine species presence, CPUE (catch per unit effort), and body condition. When? Monitoring frequency is annually, with each individual lake being monitored once every five years. Monitoring occurs in the spring of the year after snowmelt when water temperatures range between 6oC and 20oC (usually by June 15th). How? Field sampling occurs over a period of six consecutive days in a given waterbody. Ten fyke nets are set up in identified locations along the lake shoreline and are checked on a daily basis for five consecutive days, resulting in 50 trap nights for the total survey. Trap locations remain the same each day at the smaller lakes, but are relocated daily in the larger lakes to cover more area. Fish and other aquatic species caught in the fyke nets daily are given a unique fish number (up to the first 50 fish of each species caught) and data is collected on the body condition of any salmonid species present. Why? Freshwater lake fish populations are prominent components of aquatic ecosystems and a key node in the aquatic food web. Fish are sensitive to many forms of physical, chemical and biological stressors which alter fish conditions, community structure and/or biomass. In addition to the indirect impacts humans have on fish communities, there are direct impacts associated with harvesting sport fish from park lakes. Sport fish such as brook trout (Salvelinus fontinalis) are important resources to monitor from the perspective of resource management of local populations.