TORONTO, Jan. 8 (Xinhua) -- Canada's main stock index fell Monday as shares of some materials and financial companies fell.

The Toronto Stock Exchange's benchmark Standard & Poor's/TSX Composite Index lost 31.79 points, or 0.19 percent, to end the day at 16,317.65. Seven of the index's 10 main groups closed lower.

Canopy Growth Corp. surged 17.2 percent to 39.86 Canadian dollars (one CAD equals to 0.81 U.S. dollars). Aurora Cannabis Inc. rose 5.6 percent to 13.89 Canadian dollars and and Aphria Inc. jumped 14.8 percent to 21.99 Canadian dollars.

The industrials group edged down 0.1 percent, with WestJet Airlines Inc down two percent to 25.50 Canadian dollars after one of its planes was involved in an on-ground collision at a Toronto airport late last Friday. Air Canada was lost 3.2 percent to 23.88 Canadian dollars.

The energy group retreated 0.1 percent while the materials group, which includes precious and base metals miners and fertilizer companies fell 0.7 percent.

Eldorado Gold Corp declined 6.3 percent to 1.65 Canadian dollars. Nutrien Ltd dropped 3.3 percent to 66.85 Canadian dollars.

The financials group, which accounts for more than one third of the index's weight, slipped 0.3 percent, with Manulife Financial Corp declining 0.6 percent to 26.50 Canadian dollars.