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



Murman coast and the Sea of Okhotsk have a number of common littoral 

 inhabitants : Mytilus edulis, Balanus balanoides, Macoma calcarea, Mya 

 arenaria, Scoloplos armiger, Saccoglossus mereschkowskii, Travisia forbesi 

 and many others. 



In the northern part of the Sea of Okhotsk a luxuriant development of life in 

 the littoral, especially in its upper horizons, is greatly restricted by the severe 

 ice conditions in winter. This is shown in Table 316. The first horizon, which 

 is flooded irregularly by the tides, is practically uninhabited. The first zone 

 of the second horizon is also very sparsely populated ; life becomes richer in 

 the lower zone of this horizon ; and only the third horizon, which lies below 

 the average neap low tide, has a rich population. Among the sea-weeds there 

 are Idothea ochotensis and a large number of Gammaridae and Polychaeta. 

 The lower zone of the third horizon, rarely exposed at low tide, is char- 

 acterized by various red algae ; apart from those given in the table there are : 

 Chondrus crispus, Tichocarpus crinitus, Rhodomela larix, and others. Sea- 

 weeds are populated by the molluscs Margarita helicina, Lacuna vincta, 

 Cingula marmorata and others ; apart from the crabs Paralithodes, there are 

 Telmessus cheirogonus and Haplogaster grebnitzkii. The ooze on the sea- 

 floor is inhabited by Echiurus echiurus, the Polychaeta Glycera capitata, 

 Nephthys longisetosa, Brada granulata, Travisia forbesi, Pectinaria granulata 

 and others; there is a large number of Porifera, Hydroidea, Bryozoa and 

 Ascidia on the rocks. 



'The diagram of the vertical distribution of littoral organisms (in the Sea 

 of Okhotsk) is very similar to that drawn up previously for the Murman 

 coast ; this indicates that the facies of the two seas are similar, although the 

 nature of their tides differs. It is most indicative that the composition of the 

 main forms of species is practically the same in both cases. A complete 

 absence of Ascophyllum is the main difference between the Okhotsk littoral 

 and that of the Murman coast' (R. Ushakov, 1951). 



The littoral fauna of the Shantar Islands, lying in the most western corner 

 of the northern part of the Sea of Okhotsk, mainly in Yakshina Inlet on the 

 Great Shantar Island, was comprehensively investigated as early as 1927 by 

 I. Zachs (1929). The tide range in the Yakshina Inlet is about 2 to 2\ m, 

 exposing large expanses of silty-sand littoral at low tide. 



Zachs records wracks with the amphipoda Talitridae in the supralittoral 

 on the facies of cliffs and rocks. Below it, within the littoral, lies the 

 'dead' horizon; still lower are dense colonies of Fucus evanescens, Balanus 

 balanoides and Mytilus edulis. Red, green and brown algae flourish in the 

 lowest horizon. 



The soft floor littoral is also encircled by banks of wrack with innumerable 

 Talitridae. Below the supralittoral lies a wide lifeless horizon (about two 

 metres according to the range of the tide), while in the lower horizon of the 

 littoral abundant life is developed with Arenicola, Echiurus, Macoma, Pecti- 

 naria, Venus and other worms and molluscs. The colonies on the Shantar 

 Island littoral are very dense, with adult Venus attaining 500 to 800 speci- 

 mens per 1 m 2 (and even up to 1,375) ; Pectinaria from 500 to 900 specimens ; 

 small polychaetes and mollusc fry in thousands of specimens per 1 m 2 ; 



