Think of Mauritania and you are likely to imagine the burning sands of the Sahara, nomads swathed in wind-blown robes and camel trains moving through the heat haze. All correct... but don't forget the fishing fleet.
Travelling across the Sahara to Mauritania's Atlantic coast I arrive at a place called Nouadhibou. Here, where the desert meets the ocean, I see something that takes my breath away - hundreds of multi-coloured wooden boats crashing through the unrelenting surf towards the open sea.
Twenty to 30 men in each boat, hang on for dear life as their vessels are bucked skywards by waves Californian surfers might pray for.
These are les pecheurs du Mauritanie - the fishermen of Mauritania, and the country's best-kept secret.
There are many, even in Mauritania, who don't know about them but, let's face it, most Mauritanians have probably never even seen the sea. And yet off this coast are some of the richest fishing grounds in the world.
In fact thousands of fishermen work these perilous waters and have done for centuries.
Their sturdy open boats, about 40 feet long, are painted in the brightest and breeziest of colours. But don't let that fool you. This sort of fishing - mostly done at night when fish rise to the surface to feed - is incredibly dangerous. Men, indeed whole boats, are frequently lost at sea and never seen again.
Les pecheurs du Mauritanie, many of whom come from neighbouring Senegal and the Gambia, are said to be fearless. So it's with some trepidation that I join a boat one night as it sets out for the ocean deeps.
There are no lights, charts or lifejackets but the crew, 23-strong, are sprinkling the boat with water from an old plastic bottle. It's magic water from a local witchdoctor and will, I'm told, lead us to fish and protect us from danger. I try to look reassured.
Powered by an old outboard motor we head out accompanied by a sister boat - it's safer to hunt in pairs. The excitement is palpable. The men start stamping their feet and chanting: "Dolle, dolle, dolle." It means: "We are the force."
One young Gambian called Happy-Happy tells me: "We haven't caught anything for days so need a big catch tonight."
Four hours later, and 10 miles out to sea, there's splashing in the water and the tell-tale glint of fish-scales. "Herring are jumping!" the skipper shouts.
A vast net, released over the side, is dragged in a wide arc through the raging sea.
Chanting in feverish rhythm the crew start to pull the net in: "Dolle, dolle, we are the force! Be strong like a man - not like a woman." OK, it's not politically correct, but it's effective.
Eventually, our sister boat comes alongside to help wrestle in a net bursting with thrashing fish.
The waves smash us together repeatedly - wood on wood. Crunch! Anyone falling in now would be instantly crushed. "Dolle dolle. Work never killed a man - pull the net in."
Fish cascade aboard in their thousands. Soon we're up to our knees in fish, then up to our waists in slapping, flapping herring.
By dawn the two boats, full to the brim with dead fish and exultant fishermen, put into a beach next to a massive fish factory where they process and freeze fish for export. Our seven tons of herring will translate to about $50 (£30) per crewman.
Happy-Happy is, well, happy.
"Men afraid of hard work turn to crime," he grins. "Not us - we work for our rewards."
The herring, shovelled into crates, are carried ashore on the heads of young men from the factory.
Other species in the catch - groupers, octopus and small shark are sold to countless traders on the beach. Everyone wants a slice of the action. Children scamper in the shallows pouncing on fish dropped from the crates, old women - fishwives - argue over the price of octopus tentacles.
Right now, on this little stretch of beach everything, and I mean everything, revolves around fish.
The fishermen's girlfriends and wives are here to greet their men. What do they get for their trouble? Not flowers, not chocolates but - you guessed it - fish.
Fish is the language of love here and, even the currency of lust. Prostitutes, wading into the sea, are gifted fish by some of the well-muscled young men. As a means of exchange, fish is driving every transaction you could imagine - and probably quite a few you couldn't.
So, next time you think of Mauritania - don't think of camels and miles of endless desert - think of multi-coloured wooden boats crashing through massive Atlantic swells, and of fishermen chanting in vigorous unison as they take their chances in the savage seas.
Dolle, dolle - give them the force.
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