THE CASPIAN SEA 

 Table 260 



611 



Groups according to 

 origin 



Fresh water 



Marine 



Non- Non- 



endemic Endemic endemic 



Endemic 



Total 



2 

 36 

 14 

 93 



Total 



120 



10 



11 



It follows from Table 259 that the parasite fauna of Caspian fish consists 

 mainly of fresh- water species (94-3 per cent). Parasites of marine origin com- 

 prise only 5-7 per cent of the total number of species and are chiefly peculiar 

 to the herring family, Acipenseridae and bullheads. Of the 22 endemic 

 Pontic-Caspian-Aral forms only 7 inhabit the Caspian Sea alone. Of special 

 interest among these two species of northern origin are the parasite of 

 the seal Carynosoma strumosum and the Caspian herring parasite, Bunocotyle 

 cingulata, neither of which has any genetic link with the north. 



It is most characteristic that a large number (22) of the Caspian fish para- 

 sites live in fish in their larval stage and in birds when adults. This is no doubt 

 linked with the exceptional abundance of diving birds in the Caspian Sea. 

 Only eleven larvae of such species are recorded for Aral fish and only ten 

 for the Neva Inlet. The Caspian Sea is in general much richer in fish-parasites 

 than the Aral Sea. On one particular kind offish 1 19 species of parasites were 

 recorded in the Caspian Sea and only 70 in the Aral. The comparison of the 

 data on the Caspian and Aral sturgeon Acipenser nudiventris is particularly 

 indicative in this respect (before the appearance of Nitzschia sturionis in the 

 Aral Sea). 



On this subject Dogel and Bykhovsky write as follows : ' We see that not 

 one of the (first eight) specific Acipenseridae parasites has survived in the Aral 

 Sea. All the Aral parasites of the sturgeon Acipenser nudiventris have either an 

 accidental character or (Asymphilodora, Macroseroides) have moved on to 

 it from fish of different kinds.' Dogel and Bykhovsky explain the greater abund- 

 ance of fish-parasites in the Caspian Sea as compared with the Aral Sea by 

 the greater variety of invertebrates in the Caspian fauna, since the latter serve 

 as intermediate hosts to parasitic worms ; and also by the historical past of the 

 Aral Sea. On the other hand Caspian fish and, in particular, Acipenseridae 

 are poorer in marine parasites and richer in endemic and fresh-water forms 

 than Black Sea fish. 



Among the Caspian fish-parasites recorded a number of forms are harmful 

 to fisheries : Ligula, afflicting annually some millions of specimens of cypri- 

 noids ; Caligus, which causes the emaciation of carp ; Dioctophymidae larvae, 

 which form tumours in the intestines of Acipenseridae ; Eustrongylides larvae, 

 causing red boils in the muscles of pike perch, and others. 



