<P> Arguin (Portuguese: Arguim) is an island off the western coast of Mauritania in the Bay of Arguin . It is approximately 6x2 km in size, with extensive and dangerous reefs around it . The island is now part of the Banc d'Arguin National Park . </P> <P> The island changed hands frequently during the colonial era . The first European to visit the island was the Portuguese explorer Nuno Tristão, in 1443 . In 1445, Prince Henry the Navigator set up a trading post on the island, which acquired gum arabic and slaves for Portugal . By 1455, 800 slaves were shipped from Arguin to Portugal every year . </P> <P> In 1633, during its war against Spain (which then controlled Portugal), the Netherlands seized control of Arguin . It remained under Dutch rule until 1678, with a brief interruption by English rule in 1665 . France took over the island in September 1678, but it was then abandoned until 1685 . Arguin's aridity and its lack of a good anchorage made long - term European settlement difficult . </P>

The island of arguim was used by the portuguese as a