The island of Rachgoun, off the coastline of the wilaya (province) of Aïn Témouchent in western Algeria, is the main wintering site for several bird species which rest and nest in very large numbers during their migration between Eurasia and Africa. Among these are several varieties of gulls such as Larus ridibundus and Larus audouinii. The Site is home to threatened bird species including Fratercula arctica and Numenius arquata. It also provides refuge for large cetaceans such as sperm whale Physeter macrocephalus. Mediterranean tapeweed (Posidonia oceanica), a key species for various other marine organisms, covers a large area around the island. Human interventions have degraded the ecological and physical integrity of the island and its fragile ecosystem. For example, the eastern area of the island was one of the last areas in the Western Mediterranean frequented by the globally-endangered Mediterranean monk seal (Monachus monachus), until abusive fishing resulted in the disappearance of the last individual in the early 2000s.