Oct 15 (Reuters) - Canada's main stock index opened lower on Thursday, weighed down by energy stocks as oil prices slumped, while downbeat earnings from pot producer Aphria Inc further dented sentiment.

* At 9:31 a.m. ET (13:31 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 161.87 points, or 0.98%, at 16,293.53.

(Reporting by Amal S; Editing by Sriraj Kalluvila)