810 



BIOLOGY OF THE SEAS OF THE U.S.S.R. 



crab Munidopsis beringana ; the holothurian Psychropotes raripes ; Lamellisa- 

 bella zachsi, and the echiuride Tatjanellia grandis. 



The vertical distribution of the characteristic faunal communities in the 

 sublittoral and bathyal zones of the southern part of the Sea of Okhotsk is 

 well illustrated in Figs. 404 and 405. The Ophiura sarsi biocoenosis is adapted 

 to the coldest layer of the Sea. Brisaster latifrons keeps to a deeper layer of 

 warmer water (1° to 2°), and Potamilla symbiotica lives at a temperature 

 above 2°. 



Cold-water Arctic and Arctic-boreal forms are concentrated in the northern, 

 northwestern and western parts of the Sea on the shelf and in the areas where 

 water has been cooled most. Thermophilic forms are propagated in the eastern 



Cape Terpemye 



river Ozernaya 

 21 23 25 



& Echmarachmus 

 Ophiura sarsi 



Fig. 405. Distribution of bottom group and water masses on cross section from 

 southern part of Sea of Okhotsk, from Cape Terpeniye on Sakhalin to river Ozer- 

 naya in Kamchatka (according to data collected by the Gagara, 1932) (Ushakov). 



and central parts of the Sea, in both surface and deep layers which are warmed 

 by the Pacific waters which enter through the Kuril Straits, spreading north- 

 wards, northwestwards and westwards in a fanlike movement. The increase 

 with depth of the percentage of thermophilic forms and the decrease of the 

 cold-water forms is also characteristic. This is in contrast with the Sea of 

 Japan ; there the cold intermediate layer is absent, and the surface waters are 

 warmed by the Tsushima current but the deep waters, isolated from the Pacific 

 Ocean, have a much lower temperature than those of the Sea of Okhotsk. 



Gigantism is characteristic of many representatives of the fauna of the deep 

 waters of the Okhotsk Sea ; beginning with Balanus evermanni and ending with 

 Psychropotes raripes and Potamilla symbiotica, the main forms of the Sea of 

 Okhotsk are distinguished by their large size. 



F. Pasternak (1957), using the same method of zonation as Savilov, fur- 

 nishes an even more detailed picture of the distribution of bottom-living 

 fauna in the northwestern corner of the Sea of Okhotsk (Bay of Sakhalin and 

 adjacent parts of the Sea). This region is characterized by a considerable 

 complexity in its hydrological conditions. A complex picture of benthos dis- 

 tribution is created by the collision of the lower-salinity and higher-tempera- 



