Jeff, yes the sails are still around in March, but not as many. Cobia would be a good bet that time of year, but I am an inshore capt. so I am not the best person to ask about offshore fishing. I would contact Capt. Rob Gagliardi. Just search on his name on google to find his web site. He is a good offshore Capt. and will be able to tell you what would be around in the greatest numbers. Good luck and Tight-Lines.
Capt. Ron Bielefeld
Tight-Lines Inshore Guide Service
Sebastian, FL