Not a historian, someone might be able to answer this in more detail.

In general, it is very difficult to find information when the practice started. The earliest sources are mostly laws on how to deal with stranded sharks (along with whales, wood and other stranded valuables), for example Jónsbók and Grágás. Those are legal texts from the 12th and 13th century.

Incidentally the passage in Jónsbók is still in effect as law in Iceland.

Multiple sources claim that a list of the assets of a local church (Hóladómkirkja) written in 1374 included a processed shark (most likely fermented). I was unable to find the original source on this, but given the quality of material referring it, I think it's pretty reliable.

Due to the limited sources available I cannot absolutely rule out that the practice originated in Greenland, but given the available information, I'd say the chances of that are extremely slim. If this was any other subreddit I'd just tell you flat out no.

Sources:

http://www.althingi.is/lagas/144b/1281000.401.html http://www.septentrionalia.net/etexts/gragas.pdf