Use the broth of enlightment, since it is their kibble. If you use a broth of enlightment a a balm it I a insta tame, since authors take forever to eat. You can find the recipe on google or something, be warned, it is EXPENSIVE.
For those of you who play pve on official just heads up you will need to tame this guys old school since you can't pick them up with crab/megas, since you may not be able to get them to water so they stay still here's how you do it. Full ghillie and bug repellent make sure you aggro them then bring them to a spot away from other wild dinos (preferably with a drake) wait till deaggro follow them from their tail side don't get infront of their head wait till they stop moving they will stand still for a few seconds then in that instant run to them aim for their head and feed the broth of enlightenment make sure you spam triangle/E if you missed they will raise their heads and attack go away deaggro and try again I tamed 4 last night this way good luck!!
Easiest and safest way to tame this is to lure it under water. They stop aggro and you can tame as you please. Just make sure you come up for air every once in a while. Also be sure the water is deep enough.