FISHERY BULLETIN: VOL. 71, NO. I 



origin in the sediments. Geographically it had 

 a wide distribution, occurring at 72% of the 

 stations. Depth range was 27 to 201 m. Size, 

 shape, and color of Echinarachnius fragments 

 differed markedly with water depth and sedi- 

 ment type. The E. parma fragments in the 

 inshore localities were whitish, relatively large, 

 and had angular edges and corners; in offshore 

 localities, the fragments were light greenish- 

 brown, smaller, and had rounded edges. Den- 

 sities of echinoids other than Echinarachnius 

 were low, and except for Brisaster, remains were 

 found at only a few localities. Density of Bri- 

 saster remains were low but the remains were 

 rather widely distributed along the outer portion 

 of the continental shelf. Remains of Strongylo- 

 centrotus drohachiensis were sparse and widely 

 scattered in both shallow and deep water. 



MOLLUSKS 



Pelecypods ranked first in diversity of forms 

 (57 species) and second in volume of remains 

 in the bottom sediments. They were present at 

 all depths sampled, from 27 to 567 m, and were 

 widely distributed geographically. Densities 

 were high in a wide band extending from Nan- 

 tucket Shoals southwestward across the area, 

 and in a narrow band parallel to the isobaths 

 near the shelf break. Pelecypods were very 

 abundant (more than 3,000/m-) at 6 stations, 

 most of which were along the outer margin of 

 the continental shelf; common to abundant (50 

 to 3,000/m-) at 48 stations; and sparse (less 

 than 50/m2) or absent at 8 stations. In general, 

 the species with the broadest geographic distri- 

 butions occurred in highest densities. The six 

 most abundant and widely distributed pelecy- 

 pods were: Venericardia borealis, Arctica is- 

 landica, Astarte subequilatera, A. undata, Nu- 

 cula proxima, and Thyasira trisinuata. Pelecy- 

 pod shells were more abundant in moderately 

 fine-textured sediments than in either the coarse 

 or very fine sediments. Silty sand, sandy silt, 

 and sand-silt-clay yielded the highest densities 

 of pelecypod shells. Size of shells ranged from 

 10 to 12 cm (Spisula, Arctica, Placopecten) to 

 less than 5 mm {Thyasira, Nucula, Bathyarca) . 



Gastropods ranked third in volume of skeletal 



material in the substrates. Shells of gastropods 

 were distributed widely throughout the area, but 

 highest densities were near the center. A total 

 of 44 species were present, but only 2 were gen- 

 erally abundant — Alvania carinata and Cylichna 

 gouldi. Shells were taken at all depths, and 

 were particularly common between 60 and 80 m 

 and moderately common between 175 and 250 m. 

 Density was correlated in a general way with 

 bottom sediments. High densities were in silty 

 sand and sand sediments, whereas shells were 

 absent in coarse sand and mixtures of sand and 

 gravel. A large majority of gastropod shells 

 was less than 1 cm in height. 



Cephalopod remains, consisting entirely of 

 beaks, were present at only 12 stations, all of 

 which were from the outer portion of the conti- 

 nental shelf and upper part of the continental 

 slope at depths between 76 and 567 m. Densities 

 were generally less than 40/m- at the shallower 

 depths, but ranged to ISO/m^ at a depth of 366 m 

 and ll/m^ at 567 m. Remains of this group 

 ranged in size from 4 to 6 mm and were rela- 

 tively fragile. They were recovered only from 

 fine-textured sediments. 



Distributions of scaphopods were rather lim- 

 ited geographically and densities were low. The 

 two genera collected, Cadulus and Dentalum, 

 were present at 11 stations, geographically lim- 

 ited to the deepwater areas on the outer portion 

 of the continental shelf and the upper continental 

 slope. The bathymetric range was 139 to 366 m 

 for Cadulus, and 91 to 183 m for Dentalium. Sed- 

 iments at the scaphopod localities were gener- 

 ally fine-grained, but Cadulus occurred in slightly 

 coarser sediments than Dentalium. Densities at 

 the stations where they occurred averaged about 

 30 to 40/m-; maximum density for both genera 

 was 11/m-. Cadulus shells were 10 to 13 mm 

 long, and Dentalium shells were 15 to 35 mm. 



FISH 



Fish were the only vertebrates in the samples. 

 Otoliths were the main component and bones 

 were moderately common, but teeth and scales 

 were rare. Remains of 26 species were collected, 

 nearly half of which were from epipelagic or 

 mesopelagic forms. Myctophids were the most 

 numerous and widely distributed, and they con- 



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