I found this at the CITES web page. Hope this helps. Scroll down to the last FAQ on the page.
http://www.cites.ec.gc.ca/eng/sct9/index_e.cfm#11
According to the last sentence of the second paragraph it states that ""live rock" is not regulated by CITES, unless organisms from CITES-listed species are attached to the substrate". So basically it is stating that you can import live rock into Canada without a CITES permit.