Well, Sea Hunter promotions do give first attacks... and I do inflict a little bit of damage each time... but the animal *always* retreat unless it was already at very low strength. And when it retreats on high sea, you can't do anything but way until it heal a bit and comes back to you...
Didn't know that... Is it explained somewhere?
I really don't think it's just bad luck... At some point I had an outrigger standing in the middle of 4 or 5 various sea animals that attacked it each turn for many turns until I gave up (they did very little damage to my outrigger, and healed a bit before attacking again later on; if they were on coast, they'd just escape when I try to get them). I don't think I ever saw a sea animal that wasn't badly damaged not retreat over dozens and dozens of battles.