They are easy to kill if you lead them to land. Just use a spear and stab them as many times as your heart desires. However be careful cause 4 if these killed 7 of my dinos when I wasn’t paying attention.
How to kill
Step one:get into the water and have them agro on you but stay close to shore so they can’t get you.
Step two: when they are almost on the shore and can’t go any further.
Step 3: kill them with any spear like weapon.