THE SEA OF AZOV 537 



The average catch of grey mullet during the last 20 years constitutes 80 to 

 90 tons; in some years, however, it has risen to 550 tons (1923). The grey 

 mullet which feed in the Sivash are mostly young. 



Some of the anchovy entering the Sea of Azov from the Black Sea in April 

 occasionally get into the Sivash and find excellent feeding there on plankton. 

 Some dozens of tons are caught. Up to 150 tons of other pelagic fish are caught 

 in the Sivash including Atherina pontica, which feeds on plankton and on 

 some small bottom-dwellers. 



In addition it has been established that in spring considerable numbers of 

 flatfish migrate from the Sivash into the Utlyuksk inlet and the Sea of Azov. 

 Finally in some areas of the northern Sivash commercial production reaches 

 the very high rate of 100 kg/hectare. In the second (southern) part of the 

 northern Sivash the production is only 1 5 kg/hectare, while in the central and 

 southern Sivash it is insignificant. 



A certain loss of salinity might have a favourable effect on the Sivash 

 fisheries. In Vorobieff's opinion this could be achieved by separating off the 

 western and southern Sivash from its main part by dams and by digging a 

 channel through the Arabat Strelka into the central Sivash. 



A deepening of the channels connecting the Sivash with the Sea is desirable 

 in order to facilitate the entry and return of fish from the Sea of Azov. In 

 this way a wider area of the Sivash could be used for intensive fishery. 



Vorobieff estimates in the following manner the size of the main groups of 

 organisms in the northern Sivash, by applying the methods used by I. Peter- 

 sen for Danish waters : 'The total amount offish in the northern Sivash, when 

 all food is used, may be estimated at 21,000 tons. When only two-thirds of the 

 food resources are used this quantity becomes 14,000 tons.' Vorobieff esti- 

 mates the annual resources of plant food for the zoobenthos as 628,000 tons : 

 'With. 10 as a coefficient, 62,800 tons of benthos could have developed from 

 these stocks. When only two-thirds of the food is used this amount becomes 

 41,900 tons, which approaches the data actually recorded.' Further calcula- 

 tions lead Vorobieff to the conclusion that of the 1,322,000 tons of phyto- 

 plankton and phytobenthos produced in the Sivash annually only a small 

 part is consumed by animals. 



