Employee Martin Henderson walks past several plants of cannabis at Up's cannabis factory in Lincoln, Ontario, on October 12, 2018.

Canadian marijuana stocks Tilray and Canopy Growth pared deep losses Tuesday as U.S. markets continued their downward slump in October. Aurora Cannabis pared losses after falling sharply following its New York Stock Exchange debut.

Tilray fell 1.4 percent in U.S. trading, while Canopy Growth also slipped 1.4 percent in Canada. An exchange-traded fund that tracks popular pot stocks fell 2.8 percent. Known as the ETFMG Alternative Harvest ETF (MJ), the fund dropped more than 9.2 percent on Monday, its second-worst day ever. The MJ ETF is down 14 percent this month.