Situated between the village of Sidi El Abed (35 km south of El Jadida) and the small town of Oualidia, the site consists of the two lagoons of Sidi Moussa and Oualidia linked by a series of salt-harvesting pans and marshes. Although almost 40 km long, the site is extremely narrow (200–800 m) since it occupies an inter-dunal depression between two rows of dunes lying parallel to the Atlantic coast. The inland dune row is fossilized and forms a cliff of consolidated deposits up to 60 m high, while the coastal dunes are essentially mobile, but stabilized in some places by cultivation or planting. The site is fed by seawater, both through natural tidal inflow entering the two lagoons and artificially through the pumping of water into the saltpans. Fresh water enters the site through run-off from the inland cliffs and seepage from the water-table.The lagoons are relatively undisturbed and support beds of marine algae and seagrass Spartina maritima. Fringing saltmarsh vegetation includes halophytic species such as Sarcocornia perennis, Suaeda fruticosa, Atriplex glauca, A. portulacoides, Limonium spp., Spergularia salina, Juncus rigidus, etc. The few freshwater marshy regions consist of Juncus acutus, Typha and Phragmites spp. Most of the natural dunal vegetation has been replaced by cultivation, which on the inland side includes market gardening under greenhouses. Other human activities at the site include oyster farming, shellfish harvesting, fishing and tourism.
See Box for key species. The complex is an extremely important passage and wintering site for Palearctic migrants on the Atlantic coast flyway. Over 80 species have been recorded, of which 50 are regular, including two species of the Mediterranean North Africa biome (see Table 2). Gulls, terns and waders are the commonest migrants, with an average of around 10,000 waders recorded at the site. Many species must pass through the site in large numbers, but only a few are currently confirmed to have exceeded threshold levels. Nonetheless the site regularly holds up to 3,000–4,000 ducks of 11 species, and Ardea spp., Fulica spp., Platalea leucorodia and Phoenicopterus ruber are common. Numenius tenuirostris was a former wintering visitor with a maximum of seven individuals observed, but has not been seen in recent years. During the spring and summer the site is almost deserted by waterbirds and only a few species breed, undoubtedly because of high levels of human disturbance.
BirdLife International (2020) Important Bird Areas factsheet: Sidi Moussa - Oualidia. Downloaded from http://www.birdlife.org on 04/12/2020.