Skipjack—the smallest, most common species of tuna—travel in large schools through the Western Central Pacific Ocean.
Most skipjack is caught by purse seine fishing: A ship unfurls a cylindrical net around a school of fish, closes the net from the bottom, and pulls it to the surface.
The fishing vessel carries its tuna catch to a port at Kiribati, where it transfers the catch to a larger, refrigerated carrier vessel.
The carrier vessel transports the catch to Thailand, one of the world's biggest tuna processing countries (Thailand exports 40% of the world's canned tuna supply).
While much of the tuna flowing into Thailand gets canned there, US-bound tuna tends to be converted from frozen fish to loins (the meat used in canned tuna), refrozen, and packed into another carrier ship.
The frozen loins then travel from Bangkok to a cannery in the US. There, the meat is divided into cans, which are then sealed, cooked, cooled, labeled, and checked for quality. In 2015, the US imported more than 115,000 tons of tuna (worth $540 million) from Thailand).
The finished product—canned light meat tuna—is trucked to a distribution center in Southern California. From there, it's sent to grocery stores across the US.
