I went to the Riviera Maya on my Honeymoon a few years ago. Most of the time we were about an hour South of Cancun. My wife and I did a charter out of Puerta Aventura. We caught Wahoo, Mahi, Barracuda and ground fish. The charter we used was
http://www.tequilasunrisefishing.com/index.html. Great Times.
http://www.pescamaya.com/cancun-fly-fishing.html
http://www.cancunvista.com/travel/cancun_fishing.htm