In the 19th century, they set up salting works for pilchards and anchovies on the northwest coast of Spain.

BBC: Sailing in Croatia

While previously the southern bluefin were caught and canned, now they're caught and then fattened on California pilchards in some 130 underwater cages.

FORBES: The Future Is Fish

Once in the cages, it's nothing but the best for the captive fish as they gorge on the expensive imported diet of pilchards carefully chosen to maximize the tuna's oil content and bring out a pink-to-red color.

FORBES: On The Cover/Top Stories