How did supersaurus protect itself?

Kronosaurus was a 35 foot long pliOSaur. PliOSaurs were large, carnivorous marine reptiles. Being an apex predator, adult Kronosaurus would have had no enemies except perhaps other Kronosaurus. Juveniles would have been preyed on by sharks. If Kronosaurus had needed to defend itself, it could swim fast, or fight back with its powerful jaws and sharp teeth.