User blog comment:Blackendedsoul/Smoker's Bravery/@comment-3242083-20120319194521/@comment-3425840-20120319200435

That is not confirm Jinbe, his heritage was a secret till the War. As for taking him on, Smoker said that as long Ace was a pirate and he (Smoker) was a marine he won't allow Ace to go free. (Then they were interrupted by Luffy).

As for the power, yes he is powerful but not the top dog (at least at that time).