If you look on here right now they are saying that they are a waste of time but there was a recent update for them in the quality of life update makeing them 6 hour tames instead if 30 minutes hope this helps
With the update the buff lasts 6 hours. HOWEVER...
if you fast travel with a bed, you lose the buff
Liopleurodon is also aggressive to tames. It has the same ocean depth cap as a tuso (so it won't chase you to the surface) but it is passive if you're swimming