The animal communications research I'm involved with sez animals are telepathic. You too even if you're too busy to notice the effect. You read the Tatoosh story ? An honest and accurate account.

Given the fact sea lion is not there to eat you, aggression is territorial defense, maybe your SL is paranoid ?

Reorient your mind into a receptive mode, stop paddling, place paddle across cockpit, breath out audibly, and smile at the SL. Don't show your teeth, smile.

The SL will swim to your hull, grasp the bow, drag you under and eat you.