What they're good for: I'd say they're good for defense mainly. You could also take them out hunting for fish food.

Where to find: ocean water

How to tame: get a crossbow and tranq arrows. Find a shark close to shore. Shoot shark and swim to shore, swim back out into water and shoot. Repeat this until shark is down. Feed meat and narcotics if necessary. *guaranteed to not get bitten this way*

I personally tame sharks, crypod them and go back to my base where I live right next to a small lake. I put 3-10 sharks in the lake and put them on wander and aggressive mode. If anyone or anything goes into the lake, they'll be dead in seconds. Also if I happen to be getting raided while online, I pick the raiders up with my bird and drop them into the shark infested lake. :)

Max their melee damage!