Features: The Lake Simcoe population was thought to be a distinct and isolated population of Lake Whitefish (Coregonus clupeaformis). A member of the whitefish subfamily, the Lake Whitefish grows to an average length of 15 inches and a weight of .7-1.4kg. It has a brown-black back, silvery sides, and a whitish underbelly. Its head is small, with a blunt snout overhanging the lower jaw. It inhabits the cold, deep waters of the lake, except during the fall, when it moves to shallow water to spawn over the gravel shoals.

Status: Threatened Provincially (under review), Data Deficient Nationally

Range: The Lake Whitefish has a wide distribution in North America, ranging from the east coast northwest to Alaska. The Lake Whitefish (Lake Simcoe population) is only found in Lake Simcoe, Ontario. Range Maps

Threats: The Lake Whitefish has declined in Lake Simcoe since at least the 1960's according to mark- recapture studies and analysis of annual catch statistics. Accompanying the decrease in population size has been an increase in the average size of remaining fish, which suggests that the population is now composed mainly of older individuals (fish continue to grow throughout life, although growth slows as they age) as the result of very limited recent natural recruitment. This could be due to several factors, including an increase in the levels of nitrogen and phosphorus in the water, which has stimulated plant growth and changed the spawning habitat of this species, resulting in low recruitment rates. The introduction of Rainbow Smelt may have also impacted the survival rate of juvenile Lake Whitefish in Lake Simcoe.

Protection: There is no specific legal protection for this population in Ontario. The habitat sections of the Fisheries Act provide general protection. Over-fishing does not seem to have caused the decline of Lake Whitefish in Lake Simcoe, but a catch limit has been imposed and the species cannot be fished in spring or fall. In the 1980's, the Ontario Ministry of Natural Resources began an annual stocking program where eggs are collected from females, artificially fertilized, and the young raised in ponds and released into Lake Simcoe when they are one-year old. This population of Lake Whitefish will also benefit from the Lake Simcoe Environmental Strategy, a multi-agency initiative to improve and protect the health of the Lake Simcoe watershed ecosystem by improving water quality and reducing phosphorus levels to restore a self-sustaining coldwater fishery.

Text Sources: Evans et al. 1988; COSEWIC 2005

Last Modified Date: June 2008