Instead of kayakers, it could have been an Orca or a Greenland Shark.
Greenland sharks are one of the slowest-swimming sharks, which attain a maximum swimming speed that is about half the maximum swimming speed of a typical seal. Therefore, biologists have wondered how the sharks are able to prey on the seals. Evidence has been found that Greenland sharks search out seals and ambush them while they sleep. Greenland sharks have also been found with remains of polar bear, horses, moose and reindeer (in one case an entire reindeer body) in their stomachs.