Caspian Sea: State of the Environment 2019

Sea in 2012–2014 as part of a special expanded programme at more than 100 stations were used. Data show that the concentration of organic pollu- tion in the north-western part of the Caspian Sea is negligible (Monakhov 2014a; 2014b; 2015). Analysis shows that the majority of the main in- dicators of sea bottom sediment contaminants

around oil and gas facilities in 2017 were within normal background concentration ranges. 5.5. Biodiversity The Caspian Sea’s biodiversity serves as an indi- cator of its overall environmental quality and the impacts of anthropogenic pressures. Russian sturgeon. Since the beginning of the 1990s, there has been a decrease in the number and biomass of commercial Russian sturgeon re- serves, although stocks are replenished annually through artificial reproduction. The Persian sturgeon mainly occupies the feeding area of the Middle and Southern Caspian, mak- ing spawning migrations from there. In the Volga River and its tributaries, there is not an extensive population. During the high-intensity fishing pe- riod, the size of the catch does not exceed 2 to 5 per cent of all sturgeon caught. Stellate sturgeon. In recent years, the surveyed water area of the Caspian Sea has experienced a steady decline in the stellate sturgeon population. Sterlet is the only species of sturgeon whose stock has not been declining as rapidly as beluga, stur- geon and stellate sturgeon. Many large groupings dispersed throughout the Volga (from the Volgo- grad Hydroelectric Plant dam to the desalinated waters of the Northern Caspian) and geographi- cally shorter spawning migrations, allowing max- imum use to be made of all existing spawning grounds, have helped to preserve sterlet reserves. Beloribitsa is listed in the Red Book of Astrakhan Oblast. Currently, the only way to preserve and restore beloribitsa stocks is through artificial re- production. The Caspian seal (Pusa caspica) is the only ma- rine mammal and endemic Caspian species listed as Endangered in the IUCN Red List of Threatened Species 2008. At the beginning of the twentieth century, the Caspian seal population numbered about one million. Despite hunting for Caspian seals having been prohibited by law in Azerbaijan since 1952,

Atyrau

2015

RUSSIA

2015

Astrakhan

2016

2015

2010-2015

2016

Co

2016

2010-2015

2016

2016

2016

KAZAKHSTAN

Aktau

Makhachkala

2014

2016

Derbent

CASPIAN SEA

Ni

Ni

AZERBAljAN

Sumgayit

TURKMENISTAN

Baku

Cd

Cu

Cd

2015

V Cu

Turkmenbashi

Co

2012

Ni

Ni

Ni

As

AN

Cr

Co

Al

2012-2016

V

Ni

Mn

Cd

Anzali wetland

2013

2015

2015

Cu

Ag

2016

Sr

2016

Rasht

Co

2012

2013

Gorgan

IRAN

2012-2013

Cr

Sari

As

Al

V

Cu

Co

Fe

Al

Al

V

Cr

Ni

V Co

Co

Ni

Sediment fraction

the fide tor

Degree of increase in the concentration of heavy metals by the NOAA-SQuiRTs indicators

Sampling areas in sediments

Undivided sand Large silt

Toxic results Non-toxic results Oil fields, samples of 2013

26 times higher

her

Fine silt Clay silt

2 3 5 8

Coquina Coquina with sand

Sampling year

2015

Ooids

Used ERL for marine and TEL for freshwater sediments

Salt Pre-Holocene deposits and outcrops of bedrock

0

100 km

Sources: Bastami et al., 2014, 2015 and 2017 ; Brekhovskikh et al., 2017; Buchman, 2008; Guliyev et al., 2014; Jamshidi et al., 2016 and 2017; Khalilova et al., 2016; Makhlun, 2017; Pakzad et al., 2016; Salahova et al., 2015; Sokurova, 2016; Tulemisova et al., 2016; Vosoogh et al., 2017; Zaferani et al., 2015; National Atlas of Russia, 2007; SoE-Kazakhstan, 2017; SoE-Seaport Aktau, 2017.

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