With an area of 12,000 sq.km. – of which 6,300 are marine areas and 5,700 are on the continent – the Banc d’Arguin National Park (PNBA) is one of the largest national parks in Africa. It is a breeding ground for the curlew, for the maturation of the yellow mullet, and is home to many migratory birds and fish species. The park is also home to extensive intertidal and subtidal seagrass meadows. Another exceptional feature of the PNBA is the presence of the Imraguen, a population of desert fishermen. They have ancestral and exclusive rights over fishing resources as part of their traditional practices using Latin sailing boats called ‘lanches’. The importance of the PNBA in terms of biodiversity and cultural heritage requires guaranteeing its socio-ecological integrity. Aware of this situation, the PNBA managers and the Delegation for Fisheries Surveillance and Control at Sea (DSPCM) – now the Mauritanian Coast Guard (GCM) – set up a participatory maritime surveillance system in 1999.