Quite characteristic for the abyssal northern Pacific are the sea 

 stars of the family Porcellanasteridae: Eremicaster tenebrarius (up to 

 15 individuals in a trawl catch), E. pacificus and Abyssaster tara . 

 Among typical representatives of tRe biocenosis are also 

 Travisia profundi , Sternaspis scutata , Pennatula phosphorea , etc. 



The presence of the large Echiuroidea Prometor grandis is 

 characteristic for many regions of the northern (particularly the 

 northwestern) eutrophic portion of the Pacific Ocean; the large 

 proboscis of these animals extends across the surface of the sediment, 

 whereas the Echiuroidea themselves are buried in the soft bottom. In 

 this biocenosis, in addition to P^. grandis , we also see the Echiuroidea 

 Ikedella achaeta , the sipunculids-- Golfingia capitelliformis and G. 

 birsteini~ The polychaetes, usually so numerous, do not form massive 

 settlements here: We can note Travisia pupa , Kesun abyssorum , 

 Onuphis lepta , £. iridescens , etc"! Of the bi valve mollusks, 

 Malletia truncata , Myonera garetti , Nucula carlottensis , 

 Delectopecten randolphi , etc., are seen. Four species of "glass" 

 sponges are seen from the genus Hyalonema , as well as other deep-water 

 species of sponge- -Cladorhiza longispina , Abyssocladia bruuni , 

 Polymastia sol pacifica , Bathydorus laevis . The spicules of the 

 Hyalonema are inhabited by small Actinia , Ceriantharia , Ascidia . and 

 many Stephanoscyphus . Of the Pennatularia, we find the abyssal 

 species-- Umbe11uia thomsoni and Kophobelemnon stelliferum . Of the 

 Pantopoda we see HedgpethTaT articulata and Nymphon procerum . The large 

 Psychropotes and small Myriotrochus and various small Tanaidacea are 

 seen in small quantities. 



The large size of the forms included in the biocenosis 0. bathybia- 

 M. cuneata , their relatively high population and biomass indicate that 

 the benthic fauna finds good habitation conditions here and that the 

 quantity of food on the bottom can support the development of a varied 

 fauna, particularly collecting and swallowing detritophages. 



The biocenosis Spinula oceanica-Eremicaster tenebrarius is purely 

 abyssal, found in the western and central portions of the North Pacific 

 at depths of 4660-6010 m on soft, clayey silts. The macrofauna is still 

 more sparse than in the Gulf of Alaska; in particular, there are almost 

 no irregular sea urchins, the meiobenthos makes up most of the biomass 

 of this biocenosis. The leading forms are the bivalve mollusk S^. 

 oceanica , characteristic for the entire abyssal Pacific and eastern 

 Indian Oceans, particularly for the northern eutrophic zone, and the sea 

 star Eremicaster tenebrarius , which, together with E^. pacificus , is also 

 typical for the abyssal Pacific Ocean. 



The total biomass of the benthos is less than 1 g/m^, usually 0.10- 

 0.15 g/m^ (Filatova, Levenshteyn, 1961). These values of biomass are 

 characteristic for the boundary portions of the eutrophic zone of the 

 northern Pacific. 



S^. oceanica in places forms mass accumulations, up to several dozen 

 individuals in a trawl catch. The similar form S^. calcar does not form 

 massive populations. The sea stars l_. tenebrarius , E. vTcinus , 

 Abyssaster tara , Vitjazaster djakonovi are typical sTlt-eaters, almost 



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