Question

What should you do if you hook a shark while fishing in a kayak?

Answer 1

Enjoy the ride.  Depending on size of the shark, some can be safely brought close to boat after being worn out and released using dehooking device.  If that is not safe, you can cut the line as close to shark as you can safely get.

Answer 2

Depends on the shark, size, behavior, etc.. main goal is to safely remove the hook without injury to the shark and you. Last  and only last resort is to cut the line if your safety is at stake. Not many options beyond that.