Tuna are ocean-dwelling carnivorous fish in the family Scombridae, mostly in the genus Thunnus. Tuna are fast swimmers—they have been clocked at 70 kilometres per hour (43 mph)—and include several warm-blooded species. Unlike most fish, which have white flesh, tuna flesh is pink to dark red, which could explain their odd nick-name, "rose of the sea."  The red coloring comes from tuna muscle tissue's greater quantities of myoglobin, an oxygen-binding molecule. Some of the larger species, such as the bluefin tuna, can raise their blood temperature above water temperature through muscular activity. This ability enables them to live in cooler waters and to survive in a wide range of ocean environments.
From the 1950s through the 1970s, bluefin were abundant in the waters of Cuba, Bimini and Cat Cay, a few miles off the Florida coast, and were targeted by recreational fishermen, famously Ernest Hemingway and Habana Joe aboard his 1938 40-foot Wheeler named Pilar. Word spread quickly about the exciting new sport of big-game fishing. Despite the growing popularity of the sport, however, the boats of the day were hardly ideal for fighting the prized fish. Most boats used at the time were converted cabin cruisers, which were relatively slow and hard to maneuver.
Dolphins swim beside several tuna species. These include yellowfin tuna in the eastern Pacific Ocean, but not albacore or skipjack. The dolphin are believed to use the tuna schools to hide from sharks, which are tuna predators.
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