Merja Zerga or Lagune de Moulay Bou Selham is a tidal lagoon

Lagoon

A lagoon is a body of shallow sea water or brackish water separated from the sea by some form of barrier. The EU's habitat directive defines lagoons as "expanses of shallow coastal salt water, of varying salinity or water volume, wholly or partially separated from the sea by sand banks or shingle,...

 on the Atlantic

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

 coast of Morocco

Morocco

Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...

, 70 kilometers north of the city of Kenitra

Kenitra

Kenitra is a city in Morocco, formerly known as Port Lyautey. It is a port on the Sebou River, has a population in 2004 of 359,142 and is the capital of the Gharb-Chrarda-Béni Hssen region. During the Cold War Kenitra's U.S...

. Classified as a Permanent Biological Reserve in 1978, it is managed by several government agencies.

The lagoon, which covers 4,500 hectares, receives water from the Oued Drader and from the local water table

Water table

The water table is the level at which the submarine pressure is far from atmospheric pressure. It may be conveniently visualized as the 'surface' of the subsurface materials that are saturated with groundwater in a given vicinity. However, saturated conditions may extend above the water table as...

. Its average depth is 1.5 meters. The area's annual rainfall (600-700 millimeters) results in winter floods that inundate the surrounding areas.

A Ramsar Convention

Ramsar Convention

The Ramsar Convention is an international treaty for the conservation and sustainable utilization of wetlands, i.e., to stem the progressive encroachment on and loss of wetlands now and in the future, recognizing the fundamental ecological functions of wetlands and their economic, cultural,...

 site, the lagoon hosts 100 bird species and has been identified as a key site on the East Atlantic Flyway

East Atlantic Flyway

The East Atlantic Flyway is a migration route used by about 90 million birds annually, passing from their breeding areas in United States Canada, Greenland, Iceland, Siberia and northern Europe to wintering areas in western Europe and on to southern Africa. It is one of the eight major flyways used...

. Between 15,000 and 30,000 ducks overwinter at the lagoon, and it regularly holds 50,000 to 100,000 wader

Wader

Waders, called shorebirds in North America , are members of the order Charadriiformes, excluding the more marine web-footed seabird groups. The latter are the skuas , gulls , terns , skimmers , and auks...

s. Its permanent species include Asio capensis. Winter visitors include Ruddy Shelduck

Ruddy Shelduck

The Ruddy Shelduck, Tadorna ferruginea, is a member of the duck, goose and swan family Anatidae. It is in the shelduck subfamily Tadorninae...

, Common Shelduck

Common Shelduck

The Common Shelduck is a waterfowl species shelduck genus Tadorna. It is widespread and common in Eurasia, mainly breeding in temperate and wintering in subtropical regions; in winter, it can also be found in the Maghreb...

, Gadwall

Gadwall

The Gadwall is a common and widespread duck of the family Anatidae.- Description :The Gadwall is 46–56 cm long with a 78–90 cm wingspan. The male is slightly larger than the female, weighing on average 990 g against her 850 g...

, Eurasian Wigeon, Northern Shoveler

Northern Shoveler

The Northern Shoveler , Northern Shoveller in British English, sometimes known simply as the Shoveler, is a common and widespread duck. It breeds in northern areas of Europe and Asia and across most of North America, and is a rare vagrant to Australia...

, Marbled Teal, Greater Flamingo

Greater Flamingo

The Greater Flamingo is the most widespread species of the flamingo family. It is found in parts of Africa, southern Asia , and southern Europe...

, Common Coot, Pied Avocet

Pied Avocet

The Pied Avocet, Recurvirostra avosetta, is a large black and white wader in the avocet and stilt family, Recurvirostridae. They breed in temperate Europe and western and Central Asia. It is a migratory species and most winter in Africa or southern Asia...

, Grey Plover

Grey Plover

The Grey Plover , known as the Black-bellied Plover in North America, is a medium-sized plover breeding in arctic regions. It is a long-distance migrant, with a nearly worldwide coastal distribution when not breeding....

, and Slender-billed Curlew

Slender-billed Curlew

The Slender-billed Curlew, Numenius tenuirostris, is a bird in the wader family Scolopacidae. It breeds in marshes and peat bogs in the taiga of Siberia, and is migratory, formerly wintering in shallow freshwater habitats around the Mediterranean...

.