As you dip your feet, cast your line or paddle your kayak into Dezadeash Lake you might be inclined to think of it as being very deep and cold. Well, nature holds many surprises and compared to other big lakes of the southern Yukon, Dezadeash is a large shallow bathtub averaging four metres deep. The surface temperature can climb to 18° Celsius and higher in summer.
Lake trout prefer water temperature that ranges between 8º and 12˚C and cannot survive in water warmer than 23.5º C. During hot summer days, Dezadeash lake trout find themselves under much more stress than their counterparts who swim the frigid depths of nearby Kathleen Lake where surface water is rarely warmer than 11°C.
During the summer, high alpine snow patches feed the cold water streams flowing into Dezadeash Lake. This cold water, rich in oxygen, provides relief for the trout. As the climate changes, these snow patches will disappear and lake water temperatures will increase, making living in Dezadeash Lake very difficult for lake trout.
Lake Trout 101
Lake trout spend their lives in cold freshwater lakes. They grow relatively slowly (average 113 -226 milligram/year or 0.25-0.50lb./year) and live 30 to 40 years. They spawn for the first time at the age of 9-12 years old and continue for 20 years or more, though not necessarily every year. Females feed aggressively and add 20% to their body weight in order to produce eggs. Releasing big fish protects the females and future stocks of fish.
Shallow, warm water attracts migratory birds to the Dezadeash Lake outlets early in the spring. These early sources of open water creates an important staging area for Tundra and Trumpeter swans, Greater White-fronted Geese and many ducks including Green-winged Teal, Mallard, American Wigeon, Northern Pintail and various Goldeneyes.