Don't be dumb just get a boat and shoot it from there. If it catches you stab it with a spear or pike it's your only hope. Also don't try to out swim, unless you are level 100 and you have a sick water creature. :)
Once I found one while playing the island at level 92. It took awhile but I eventually got it down. But while I was putting meat in its inventory I realized I must have accidentally hit it because the taming effectiveness was at 88% instead of 99%
believe it or not, if you have enough agility and time it is possible to kill one of these sharks. i used my ichthy (who was around level 17) to kill one of these pain in the asses. the shark was around 28 in levels.
For a low level you can use an ichy to lead one of these suckers to the shore and then just tranq it from land, just be mindful about any other water tames (or wild creatures) that might interfere. They're pretty slow and their bite isn't too devastating, but when you're swarmed they can prove to be deadly. I would recommend you knock it out in shallow water so you can keep an eye on its torpor without losing too much oxygen, and bring plenty of meat/narcs if you don't have kibble. They make good defenders if you have your tames in an open body of water and as long as you have enough of em