Ark devs heres a cool idea; here are the three degrees of taming

1. Passive tame

2. Knock out

3. Cannons, boulders, rockets

So mosa is tranq, making astrocetus cannons

And the ichtyosaurus (dolphins) are passive tame so this should be tranqs

Or you could make us mad and make it passive tame, and have to use tek jetpsck or trap to tame