The oceans off West Africa are teeming with life. Fish is a staple of many diets in the region and accounts for the livelihoods of hundreds of thousands in countries like Senegal and Sierra Leone. But their way of life is increasingly under threat, as far from the shore, industrial vessels trawl in huge quantities of fish illegally. Greenpeace describes the situation as a "Wild West in Africa's oceans". FRANCE 24 went aboard the Esperanza, the ship tasked with investigating the crisis.