Fishermen call them giants for a good reason: The bluefin tuna is the largest of the commercially harvested tuna species, with a record weight of just over 2,000 pounds and a length of over 12 feet. This fast-swimming migratory species occupies temperate and tropical waters worldwide. Over half the global catch comes from biologically separate stocks in the eastern and western Atlantic Ocean. The Mediterranean is also a historic area for bluefin. Bluefin is caught by a variety of gear types, including purse seine, harpoon, longline, troll, handline and rod and reel. The giant bluefin has a blue-black upper body and silvery white coloring on the sides and belly. The finlets are edged in black. Despite its potential large size, commercially caught bluefins are usually between 200 and 400 pounds. Bluefin is graded by taking “plugs” of flesh to test for fat content and color, critical factors in the price structure.