Carry it to a pre made taming cage with an argy (the argy will be able to gank hits whilst carrying easily) then drop the Baryonyx in, and ez tame it. Also, don't use fish meat li,e everyone else is saying. Just use regular kibble.
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.