The most commonly caught Tuna off the South Florida Coast is the Blackfin Tuna, Skipjack Tuna and the Bonita. All three range in size from 5 to 25 pounds and put on an excellent fight, the Blackfin Tuna is the only one of the three that I would consider good to eat. The Bonita will usually be found in less than 200 feet of water, the Blackfin and Skipjacks will generally be found in deeper waters.
During late winter and early spring the Yellowfin Tuna will be passin through, usually found way offshore in the deep blue waters of the Gulfstream, these Tuna will range between 50 and 150 pounds, some will get to 200 pounds. The Yellowfin Tuna is an excellent eating fish and quite often what your eating in your favorite sushi restaurant.
Pound for pound the Tuna regardless of size is one of the toughest fighting fish in the ocean, all the way to the boat and then some.