I was in Mexico for three weeks to photograph sailfish by the island Isla Mujeres and Cenote (both in Yucatan - starting off point is Cancun). With Lufthansa the flight is straightforward from Frankfurt to Mexico City, and then on with Mexicana to Yucatan - Cancun. I must recommend Mexicana! The ticket for Business Class is so cheap, that Lufthansa does not give miles for it ;-)))
The sailfish come to the coast of Yucatan at the start of each year to hunt sardines. They hunt the smaller sardine swarms in a group, and pick individual fish out of the swarm with their spear. A spear thrush stuns the sardine, which is then devoured as though they would run out tomorrow.
The best sailfish - marlin photos of mine on Seatops: