As Kathie already said more information is definitely needed to make any positive ID's.
To give you an idea, in the 1891 Census of Canada, not including spelling variations, abbreviated forms of the name James, other errors in the originals or in indexing, there are at least 75 individuals named James Fraser born 1875-1885. This number also does not include people born in Newfoundland which was not part of Canada until 1949 - and depending on the source of the information that he was 'born in Canada' they might not distinguish that fact.
The fact that he was Merchant Marine without knowing the name of the ship he was on is not particularly helpful - this page at the Library and Archives Canada talks more about researching members of the Merchant Marine.
It is difficult from the little information given to even make any good assumptions on where even to look... there are so many different inferences one could possibly make... A somewhat Scottish sounding name and the claim of being "half-Indian" certainly makes me think of the Scottish settlements in the prairies in the late 1800's, but the name Fraser is also exceedingly common in Nova Scotia which has it's own substantial Métis communities.
Service in the Merchant Marine could equally point to someone who grew up on and around ships, favouring someone from the coastal provinces, or to a person who simply wanted to get as far away as possible from prairie life. The Merchant Marine tended to attract people who were not eligible to serve in the armed forces and those that were already employed on commercial vessels. In the years before the war James might already have been a sailor.