Boats of the Mackenzie River watershed carrier business in 1947. The last steam-propelled sternwheelers, the "S.S. Distributor" and "S.S. Mackenzie" were retired around the same time. In later years, with the construction of the Mackenzie Highway from Alberta to Great Slave Lake, the importance of the Athabasca-Slave River route dwindled and NTCL operations were based from shipyards in Hay River after 1959. NTCL became the primary water operator in the Mackenzie River watershed with the purchase of Hudson's Bay Company's fleet and equipment in 1958, and the total buyout of Yellowknife Transportation Company in 1965 including its fleet of diesel tug boats. Other small commercial operators
Mackenzie River and riparian habitat. There are 53 fish species in the basin, none of them endemic. The Mackenzie River has a similar range of fish fauna to the Mississippi River system. It is believed that the two river systems were connected during the Ice Ages by meltwater lakes and channels, allowing fish in the two rivers to interbreed. Fish in the Mackenzie River proper include the northern pike, several minnow species, and lake whitefish. Fish in the southern half of the watershed are genetically isolated from those of the northern half due to large rapids on the Slave River preventing fish