yah theybeen catchin em for last couple weeks pretty good, a tournament about two weeks ago had about 250 sails released by a little over sixty boats in two days. But u might want to fish out of islamorada or key largo this time of year, rather than marathon, not to say you couldnt have a world class day out of marathon.
they catch blackfin out on the lumps along with scattered wahoo and dolphin and the occasional blue or white, but sailfish is the hot ticket this time of year, the flats and back bays arent doing anything spectacular usually
I read a report that they saw baitballs so thick that you could have walked on them. Another report was that it was the best Sailfishing they have seen in 15 years. I would say that if you can get out there and find the bait you will find the sails