This site lies in the flood-plain of the Oued El Kebir and the Oued Bou Namoussa, just to the west of Lac des Oiseaux (site DZ005). It is the second-largest remaining freshwater marsh in Algeria, exceeded in size only by Marais de la Macta (site DZ017) and in winter the area of flooding and emergent vegetation is greater than that in La Macta. The marsh lies just above sea-level and is separated from the sea to the north by a sand-dune system through which the Oued Mafragh flows north into the sea. Water flows into the marsh from the east via the Oued El Kebir and from the south via the Oued Bou Namoussa and Oued Chourka Garaet. There is seasonal pattern of winter flooding and gradual drying out, with the marsh dry for at least three months between June and November. The water-level is usually less than 1 m and does not normally exceed 2 m. There is open water at the edge of the marsh, where it is grazed by cattle, and this extends into the middle in some places, but c.90% of the area is covered by emergent vegetation, dominated by Scirpus littoralis, S. lacustris, S. maritimus and Juncus sp. Phragmites communis is also widespread and Typha angustifolia, Glyceria fluitans, Carex sp. and Alisma plantago-aquatica also occur, as well as a national rarity, Butomus umbellatus. Submerged vegetation includes abundant Myriophyllum sp., Chara sp., Nitella sp., Ruppia sp., Callitriche sp., Zanichellia palustris and Ranunculus sp. There are scattered Tamarix sp. and Lemna minor. At the northern end of the marsh there is a saline area with Salicornia sp. and, at the base of the dunes, a strip of Alnus forest. There is considerable disturbance on the marsh, caused by large numbers and a high frequency of hunters shooting wildfowl in the winter. There is some pasture and cultivation and heavy grazing by sheep and cattle around the periphery.
See Box for key species. The site is said to be difficult to count (especially in the breeding season) because of its extent and the dense vegetation, so many counts are almost certain to be underestimates. Marmaronetta angustirostris has been observed on the site in winter in small numbers and up to 20 individuals have been observed flying over the site in July. Aythya nyroca is present in small numbers in the breeding season and ‘probably breeds’, as does Oxyura leucocephala.The site regularly holds 30,000 or more wintering waterbirds (39,800 in 1978 and 39,400 in 1986). The numbers of Anser anser are especially significant as the whole Central European breeding population (estimated at 25,000) is believed to winter in only three sites in the Maghreb (Marais de Mekhada, Lac Fetzara (site DZ008) and Lac Ichkeul in Tunisia). In addition to the species in the Box, there are significant numbers of wintering Anas crecca (over 5,000 in 1998) and Fulica atra (12,300 in 1998) and a variety of wintering Charadrius and Calidris waders. Breeding birds include Botaurus stellaris (known to breed from only three other North African sites), Ciconia ciconia, Glareola pratincola and Circus aeruginosus and the site is an important feeding area for Bubulcus ibis and Egretta garzetta from the breeding colony at Bou Redim (site DZ004). Other ‘probable breeders’ include Tachybaptus ruficollis, Ardeola ralloides, Bubulcus ibis, Egretta garzetta, Ardea purpurea, Plegadis falcinellus, Anas platyrhynchos, Rallus aquaticus and Fulica atra. Over 1,000 individual Bubulcus ibis seen on the site in 1976 may have been nesting just outside the marsh and 3,000 individuals seen in July 1984 were thought to be breeders displaced from Bou Redim. The only two Phoenicopterus ruber recorded from this site (in 1978) were subsequently shot.Raptors recorded from the site include ‘impressive flights’ of Gyps fulvus and smaller numbers of Milvus migrans, Circaetus gallicus, Circus aeruginosus, Buteo rufinus, Hieraeetus pennatus, Pandion haliaetus and Falco eleonorae. Motacilla flava is said to ‘nest in great numbers’, but there are no details of any counts.The site is closely linked to Barrage de la Cheffia (site DZ007) and birds (notably Anas penelope) move between the two sites, using Barrage de la Cheffia as a refuge when there is intense hunting on the feeding grounds of Marais de Mekhada. The huge number of 95,000 A. penelope observed on Barrage de la Cheffia in 1974 were thought to be taking refuge from Marais de Mekhada because of low water-levels making it unsuitable as a roost. Birds also move from this site, when hunting is taking place, to Lac des Oiseaux (site DZ005), or sometimes take refuge on the sea (including Anser anser). This latter species may also be displaced to Lac Fetzara (site DZ008) by hunting disturbance.
Non-bird biodiversity: None known to BirdLife International.
Pressure/threats to key biodiversity
The site lies outside the boundary of the Parc National d’El Kala, although it is clearly part of the El Kala wetlands complex, linked hydrologically and ornithologically to other sites (sites DZ001–DZ004 inclusive) within the park and to Lac des Oiseaux (DZ005), which also lies outside the park boundary. In addition to the serious disturbance caused to wintering species by intense hunting pressure, the marsh habitat is also threatened by drainage. There appears to be no history of attempts to drain this marsh specifically (which is probably a contributory factor in its current conservation importance), but proposals to dam the Oued El Kebir at Mexanna (to provide domestic water for the city of El Kala) could have a serious detrimental impact. The water-supply into the Marais de Mekhada from the Oued Bou Namoussa has already been interrupted due to the construction of the Barrage de la Cheffia and a dam on the Oued El Kebir is likely to reduce substantially the frequency, duration and depth of flooding on the marsh. In the winter of 1985–1986, the construction of a road between Annaba and El Kala had the opposite effect, blocking the outflow to the sea and raising water-levels in the marsh. There have been calls for the marsh to be included within the National Park, especially in view of its importance for wintering Anser anser, and there are proposals for the site to become a Ramsar Site and a Natural Reserve.