Estuarine ecosystems: conservation needs and economic significance

International audienceEstuaries represent strategic locations for human activities (e.g.: village settlement, tourism, industries....) and are thus particularly impacted, being often separated from the sea (e.g. by construction of road damns), subjected to chronic or point-source eutrophication and chemical or organic pollution, e.g. from chemically contaminated water, sewage, or use as dumping sites. The integrity of the ecological functions of estuaries, notably in respect to providing necessary ecosystem service can come easily under pressure of coastal development is not properly planned and managed. Soqotra is no exception to that but unfortunately rather little has been known about the ecology and biota of the islands "khors" until recently. Estuarine and lagoon surveys of Soqotra Island and the Hadhramout coast of Yemen were conducted since 2007 with the objectives to provide baseline data on estuarine and lagoon fish diversity, especially in support of informed conservation management. A total of 66 species in 31 families have been recorded, among which 64 species in 30 families were from Soqotra and 20 species in 13 families were from the mainland. 23 species represent new faunistic records and the most common species is Terapon jarbua (Forsskål, 1775). Including the critically assessed historic records the total fish diversity of estuaries and lagoons of Soqotra Island is estimated at 75-80 species, which is relatively higher compared with species inventories of well-researched coastal estuaries from South Africa. The high number of economically relevant species of fish recorded to date underscores the paramount importance of these coastal water bodies as spawning and/or nursery sites, and for the sustainability of vital provisioning ecosystem services