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NOUAKCHOTT, Nov 6 (Reuters) - At least 47 migrants died trying to reach Spain's Canary Islands after drifting for more than two weeks off the west coast of Africa in two boats, police sources in Mauritania said on Tuesday.

Mauritania soldiers discovered 42 bodies in the sea near the northern port city of Nouadhibou, which lies on the frontier with Western Sahara, the sources said.

Five more migrants died after being taken to hospital, but authorities were able to rescue 96 others, who were being held in a detention centre in Nouadhibou and were due to be repatriated within the next 48 hours.

"They had been at sea for 19 days," said one of the sources. "They are mainly Senegalese, Gambians and Malians."

Authorities believe the vessels set sail from neighbouring Senegal, and was travelling northwards along the African coast before attempting the 110 km (70 mile) crossing to the nearest island, Fuerteventura.

Scores of illegal migrants, desperate for a better life in Europe, pay thousands of dollars each for a place in one of the overcrowded, rickety wooden fishing boats which attempt the perilous trip.

Hundreds of impoverished West Africans perish each year in the arduous journey. The people-smuggling networks that control the routes often fail to provide vessels with working engines or enough fuel for the voyage. (Reporting by Ibrahima Sylla; Writing by Daniel Flynn; Editing by Nicholas Tattersall and Mary Gabriel)

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