Caspian Sea: State of the Environment 2019

Table 5.3: Biomass of the Middle Caspian zoobenthos (g/m 2 )

Organism

2010

2011

2012

2013

2014

2015

2016

Vermes

5.5

7.93

10.8

2.81

3.48

6.53

4.13

Crustacea

10.1

13.47

17.93

10.12

12.06

9.02

8.12

Mollusca

4.0

8.11

12.05

11.36

5.13

20.48

7.16

Total

19.6

29.51

40.78

24.29

20.67

36.03

19.41

Source: Azerbaijan Scientific-Research Fisheries Institute.

Table 5.4: Zooplankton numbers (specimens/m 3 ) and biomass (mg/m 3 ) in the Azerbaijan sector of the Caspian Sea

Middle Caspian

Southern Caspian

Year

Number (specimens/m 3 )

Biomass (mg/m 3 )

Number (specimens/m 3 )

Biomass (mg/m 3 )

10,323.2

275.4

3,326.7

88.1

2011

10,620.8

301.8

4,005.7

104.3

2012

12,747.5

312.9

4,109.0

102.8

2013

11,620.5

308.6

4,225.7

110.5

2014

12,116.4

352.4

3,835.2

96.9

2015

11,903.3

347.8

3,753.6

106.3

2016

Source: Azerbaijan Scientific-Research Fisheries Institute.

in autumn. Herrings and sprats come to the Yala- ma-Shabran zone of the Middle Caspian coast for breeding. This area belongs to the mixing zone, at a depth of 10–50 m. During spring, young stur- geon also flock here to feed. Areas along the west- ern coast of the Middle and Southern Caspian are home to sturgeon wintering and feeding grounds in shallow marine pastures which are 10–40 m in depth. The entire western coast of the Middle and Southern Caspian can therefore be considered a zone of sensitive fish habitats. The aquatic biological resources industry in the Volga-Caspian fisheries region of the Russian Federation is based primarily on semi-migratory fish species. It has been established (Ivanov 2000) that annual stock replenishment depends on the

Given the distribution of fish habitats, there is a need to distinguish between breeding grounds, feeding grounds and wintering grounds. The western coast of the Middle Caspian (Azerbaijan sector) plays a decisive role in the formation of the ichthyofauna of the entire sea. Here, at depths of 10–50 m, are silty-sandy, sandy-silty and silty- shell soils, which are considered to contain the highest populations of benthic feed organisms. It is therefore in this area that the juveniles of mi- gratory and semi-migratory fish concentrate for feeding. In addition, male fish frommigratory and semi-migratory species gather ready for breeding in this area of the Middle Caspian, close to the mouths of the Terek, Samur and smaller rivers. The region becomes particularly important during the spring-summer period, and to a lesser extent,

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