THE BARENTS SEA 117 



Table 49 



T. Gurjeva notes that on sectors open to a heavy swell some forms of the 

 littoral fauna rise to higher levels, passing even into the supralittoral ; others, 

 on the contrary, disappear. Thus in places where the swell is violent, Asco- 

 phyllum nodosum disappears almost completely, and is replaced by Rhody- 

 menia palmata. It is interesting that the biomass is considerably increased by 

 sea mussel both in places of a strong swell and on protected sectors. T. Gur- 

 jeva assumes the existence of two biological races of sea mussel. 



T. Matveeva gives some interesting data on the seasonal changes of the 

 population of the rock littoral. The growth of the young in the summer 

 months is first to be noted. It is natural that the highest fluctuations (two or 

 three times) are given by the algae. In autumn and winter the number of 

 Littorina decreases considerably ; only a few forms such as Asterias rubens 

 and Buccinum groenlandicum migrate into the sublittoral. According to 

 T. Matveeva's observations, by the end of the summer many gastropods, 

 Margarita helicina, Lacuna divaricata, Trophon truncatus, Natica clausa, 

 and the crab Hyas araneus migrate to the sublittoral. About the same time 

 Nudibranchiata (Doto coronata, Coryphella rufibranchialis, Dendronotus 

 frondbsus, Acatodoris pelosa) appear in large numbers. Many components of 

 the littoral fauna go under cover in winter, hiding under rocks or even bur- 

 rowing into the bottom, as for example Nucella lapillus, Rissoa aculeus and 

 others. 



The winter weakening in the growth of laminaria and the change of condi- 

 tions bring about the migration of some inhabitants of the upper level of 

 the sublittoral into the deeper layers. For instance, the mollusc Lacuna vincta 

 (V. Kuznetzov, 1 948) is apt to perform such seasonal migrations. 



In the soft soils of the intertidal zone of the western Murman, the burrow- 

 ing bivalves and annelid worms in various forms inhabit the sea-weeds cover- 

 ing the beach (Enteromorpha, Monostroma and others). Among the members 

 of onfauna* Iaera marina, Gammarus locusta, Littorina rudis, Skeneaplanorbis, 

 Hydrobia ulvae, Limapontia capitata, Mytilus edulis may always be found here. 

 The upper layer of the soil and the turf-like seaweed beds are inhabited by 

 innumerable minute Fabricia sabella and Manayunkia polaris and by large 

 Cardium edule. The polychaetes Pygospio elegans, Arenicola marina, Polydora 

 quadrilobata, Scoloplos armiger, Ophelia limacina, Travisiaforbesi, Terebellides 

 stromi, the hypherian Priapulus caudatus and Halicryptus spinulosus, and the 



* Danish and English authors use the terms onfauna and infauna to distinguish the 

 fauna living on the bed and in the bed. 



