If you are just getting started with baitcasting, then we recommend that you go with a monofilament line. It is much easier to cast than some of the other alternatives like braided line or fluorocarbon, because it is a bit easier on the thumb when you are controlling the cast.
Having said that, the strength of your line and the amount of it will both be determined by what kind of fishing you are doing, so it might be worth it to do a bit more research before you cast off for your next offshore fishing trip.