Caspian Sea 2011

State of the Environment of the Caspian Sea

do not stay for long in the Caspian Sea region. In total, approximately 160 - 170 species of wa- terfowl can be found in the area. Recently, water- fowl numbers have slightly decreased, but they can still be counted in their millions. No endemic species are found. Thirty seven species are listed in the National Red Data Books. In various parts of the coastal areas of the Caspian Sea, between 45 and 70 species of Mammals can be found. However, there is only one marine mammal – the Caspian seal. There are also a few other spe- cies inhabiting wetlands and river systems. The Russian muskrat ( Desmana moschata ) inhabits deltas of the Volga and Ural rivers. It is very rare and listed in the Red Data Books. Water shrew ( Neomys anomalus ) inhabits the southern coast of the Caspian Sea. Water vole ( Arvicola terrestris ) is very common around the coast of the Caspian Sea. Castor ( Castor fiber ) can only be found in the Volga Delta and is considered to be very rare. Coypus ( Myocastor coypus ) and muskrats ( Ondatra zibethicus ) were introduced from North America. Coypus inhabit the deltas of the Kura and Len- koran rivers, while muskrats are very common all around the Caspian Sea. Otters ( Lutra lutra ) are considered to be rare, and found in the deltas of all the main rivers. Euro- pean mink ( Mustela lutreola ) is also very rare. It only inhabits the deltas of the Volga and Ural rivers and is listed in Kazakhstan’s Red Data Book. American mink was introduced into the region and is now taking over habitats of the European mink. Many other mammals are found in reedy areas, but these are not connected to water habitats. The Caspian seal is the only marine mammal in the region and is an endemic to the Caspian Sea. It is listed in the IUCN Red List, but not in the Nation- al Red Data Books. It can be found in all parts of the Caspian Sea, but during winter, the pupping season is concentrated on the ice in the North Caspian. It feeds on kilka and other small fish found throughout the Caspian Sea, and undertakes a regular seasonal migration from north to south (UNDP 2004).

The total number of Caspian seals was estimat- ed to be more than a million at the beginning of the twentieth century, but it was reported that this number had decreased to 350,000 - 400,000 by the late 1980s (Krylov, 1990; KaspNirkh annu- al reports, 2002–06). Surveys of pup populations during the period 2005 - 2008, plus historical census analyses and hunting records, indicate that the total number of seals in the Caspian Sea had declined in 2005 to approximately 111,000, with an average annual decline of about 4% over the past 50 years. The main causes of this population decline are disturbance in the seal’s ecosystem and pollu- tion. One of the major food sources for the seals is the tulka. Over the years, tulka stocks have re- duced dramatically: as a result, the food chain of the seals has been disturbed (CEP 2007g). Most of the priority seal habitats and shore (‘haul-out’) sites around the Caspian Sea have yet to be fully inventoried and documented. The CISS survey team has assessed the distribution of seal pups and breeding seals on the ice every year since 2005. However, stakeholders are not familiar with priority seal habitats – nor do they know how many seals currently use particular shore sites or the extent of habitat disturbance or degradation (UNDP 2004). Invasive species The introduction of alien species has occurred both accidentally and intentionally in the Cas- pian Sea. Between 1930 and 1970, at least 20 species of fish were intentionally introduced for economic purposes. The most significant invasions, causing consid- erable ecological disruption were: The invasion of diatom algae Rhyzosolenis [=Pseu- dosolenia] calcar-avis in the 1960s. As a result, the numbers and distribution of many native phyto- plankton species have been reduced. Rhyzosole- nia has become a dominant phytoplankton.


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