The history and future of the biological resources of the Caspian and the Aral Seas

摘要

The term ‘biological resources' here means a set of organisms that can be used by man directly or indirectly for consumption.They are involved in economic activities and represent an important part of a country's raw material potential.Many other organisms are also subject to rational use and protection.They can be associated with true resource species through interspecific relationships.The Caspian and Aral Seas are continental water bodies,giant saline lakes.Both categories of species are represented in the benthic and pelagic communities of the Caspian and Aral Seas and are involved in human economic activities.The most important biological resource of the Caspian Sea and the Aral Sea is their ichthyofauna,represented by both aboriginal species and species introduced by man in the 20th century.Among invertebrates,the main biological resource of these saline lakes is the brine shrimp Artemia.The physical state of the Caspian as a water body is relatively stable but its biological resources are very seriously affected by irrational use.The Aral Sea since the second half of the 20th century has experienced catastrophic anthropogenic regression,which has led to the almost complete loss of its biological resources due to salinization.However,thanks to efficacious engineering measures,it has now become possible to preserve its northern part (Small Aral)and rehabilitate it,lowering the salinity to its former state.The result has been the restoration of its fish biological resources.In the southern part of Aral (Large Aral),which turned into a group of separated hypersaline reservoirs,the only resource species currently available is the brine shrimp Artemia.The main environmental threats for biological resources of the future Caspian and Aral as well as potential solutions are considered.