The tunny fish is a large, active creature up to 3 meters long and sometimes weighing as much as 450 kilograms. It lives in both warm and temperate seas and has a body temperature well above that of the water in which it swims. During mating season thousands of tunny fish gather together along the coast of Europe and America in the Atlantic Ocean or in the Mediterranean as far as the Black Sea.

In the Mediterranean fishermen use a very old method of catching tunny fish. This involves rigging a system of nets which forces the fish to swim into an enclosed space known as the death chamber.

When the fish have reached this place the nets are raised out of the water and the killing process, known as the mattanza, begins. This fish are killed with spears and harpoons and then hoisted on to waiting boats. It is a rather exhausting way of fishing but the catches are usually large and profitable, for tunny fish is very tasty and in one season more than 1,000 tons can be caught.