As a historic port town, Concarneau owes its economic rise to fishing. After several centuries of boats fishing for sardines, deep-sea vessels began fishing for tuna. The town then specialised in the more profitable trawling of the Atlantic and Indian Oceans.
Concarneau has an important fishing port (Port de Pêche). It is the largest fishing port for tropical tuna. White tuna is caught between the Azores, Ireland and the Bay of Biscay. Yellowfin tuna is caught by tuna seiners off the coast of sub-Saharan Africa or in the Seychelles.