I usually use my high level starco (lv 130) to clear out the area then I knock it out from the shallows. They long agro range some careful to remember which one is high level... I'm actually typing this right after I knocked out lv 108!
These are actually really easy to tame. Find one and lure lure it closer to the shore and then just stand on land where u are safe and keep shooting it. Make sure there are no other sharks or mantas that can hurt you while taming your shark. Good luck