Past, Present and Future of the Aral Sea -A Review of its Fauna and Flora before and during the Regression Crisis.

We review the past, present and possible future of the Aral Sea system in context of the human caused regression crisis that resulted in the drying out of the larger part of this original brackish water sea. The results are put into the context of other threatened saline lakes and the general water crisis in the world due to overexploitation of water resources and climate change. We cover the geographic history and hydrology from the origin of the sea 17,000 years ago to the present. The original biota including animals, higher plants and algae are covered in full detail, and tracked through the regression crisis. We put special emphasis on fish and fisheries because of their economic importance for the surrounding populations. We also review the side effects of the regression in terms of human health and changes to the terrestrial environment and local climate. We explain the dramatic improvements to the fauna in the northern Small Aral Sea following the construction of dams to retain its waters and discuss future options to further improve this restored water basin. We contrast this with the progressing hypersalinization of the remnants of the southern Large Aral Sea, which faces conditions that will eventually render a "Dead Sea" condition hostile to all metazoan life. We end by highlighting the partial restoration of the Small Aral Sea as an example of how much restoration can be achieved for relatively little financial expense and in a short period, when good ideas, kind hearts and hard work operate together for the benefit of the environment and our human society.

Crustacean Fauna of the Aral Sea and its Relation to Ichthyofauna During the Modern Regression Crisis and Efforts at Restoration.

The regression and salinization of the Aral Sea, largely caused by water diversion for irrigation, is among the most severe ecological disasters of the 20th century, and has had severe health and economic consequences for the local population. Introductions of alien species to enhance commercial fisheries before the regression had already impacted the ecology of this system. Crustaceans made up about one-quarter of the original metazoan species and constituted the principal food for native and introduced fish. From 1960 on, crustaceans were recorded at numerous fixed sampling stations, including thanatocoenoses (dead animals from sediment cores). We use this previously unpublished information to document changes in species abundance and discuss their causes in the context of species interactions and changes to physical and chemical parameters. Competition from alien crustaceans led to declines in or even extinction of some native species, but eventually severe salinization became the main detriment, and resulted in the complete collapse of commercial fisheries. This seriously hurt a critical trade, which provided the principal protein source for the local population. We document how comparatively modest conservation efforts enabled the northern Small Aral Sea to partially recover and commercial fishing to resume.