Get a parasaur and level up speed ,bola and tranquilliser (arrows and darts work best) and lots of fish I recommend building a mortar and pestle to keep them down. Bola then on the parasaur and use them as mild defence against bugs and dilophosaurs tranq and of it escapes run on parasaur and repeat process until down then feed fish and keep eye one torpidity and you should have one of the best companions ever
1: Do not fight them in water under any circumstances
2: Lure them on to land
3: Use a bola
4: Attempt to Tranquilse with bow and arrow or better
Remember: They can only be tamed with fish meat and they usually kill all the fish in the area so you should probably have some prepared beforehand.