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NOAA Technical Report NMFS 140 



ately large (10-17 mm) and abundant tube-dwelling 

 inhabitant of continental shelf sandy substrates. It is 

 very important in demersal fish diets. 



Unciola irrorata (Say) (Fig. 247), another moderate-sized 

 (10-13 mm) tube-dwelling gammaridean amphipod of 

 the family Aoridae, is abundant in the sands of Georges 

 Bank and is also very important in demersal fish diets. 



Crangon septemspinosa Say (Fig. 247), the sevenspined 

 bay shrimp, a moderately small (5-8 cm) caridean 

 shrimp of the family Crangonidae. It is typically found 

 in sandy sediments of the region in both inshore and 

 continental shelf waters, and in certain localities is very 

 abundant. This shrimp is a very important prey to nearly 

 all demersal fishes. 



Homarus americanusH. Milne-Edwards (Fig. 247), the 

 American lobster, is, together with the sea scallop, one 

 of the most commercially valuable invertebrate resources 

 of the northwest Atlantic. It is widely distributed through- 

 out the New England region from inshore bays and 

 sounds to the offshore canyons bisecting the edge of 

 the continental shelf. Size of mature lobsters ranges 

 from around 25 cm average length, for individuals cap- 

 tured for market by the inshore fishery, to very large 

 (sometimes in excess of 80 cm), for specimens in the 

 offshore stock; minimum legal size for capture is cur- 

 rently 8.13 cm (3.25 inch). Lobsters are scavengers and 

 inhabit a variety of substrates. 



Hyas coarctatus Leach (Fig. 248), the arctic lyre crab, 

 is a moderately small (to 31 mm) spider crab in the 

 family Majidae. This species is common throughout the 

 New England region on muddy and pebbly bottoms. 

 Small individuals have been reported to occur occa- 

 sionally in the diet of long-horned sculpin. 



Pagurus spp. (Fig. 248) comprise seven species of 

 pagurid hermit crabs resident in the New England re- 

 gion. The species of the genus Pagurus in the family 

 Paguridae represented in this study include P. acadianus, 

 P. anmdipes, P. arcuatus, P. longicarpus, P. politus, P. polMcaris, 

 and P. pubescens. The represented species range from 

 small to medium in size (9-31 mm, carapace length), are 

 ubiquitous throughout the region in nearly all substrate 

 types, and are preyed upon by bottom fishes. The most 

 common and broadly distributed species is P. acadianus. 



Cirolana spp. (Fig. 248), comprise three species of 

 the isopod crustacean family Cirolanidae resident in 

 the study area (C. concharum, ('.. impressa, and C. polila) 

 along with several others identified only to the generic 

 level. These moderately small (16—23 mm) crustaceans 

 are fairly common on muddy and sandy bottoms in the 

 Gulf of Maine and on Georges Bank. They are prey to a 

 variety of demersal fishes. 



Phylum Echinodermata 



Asterias vulgaris Verril (Fig. 248), the northern star- 

 fish or purple star, is one of the most common star- 



fishes inhabiting the offshore waters of the New En- 

 gland region and is a member of the family Asteriidae. 

 This is a large species commonly between 15 cm and 30 

 cm (6-12 inch) in diameter; some specimens up to 42.5 

 cm (17 inch) have been reported from the northern 

 limits of its range. It is normally found on sandy bot- 

 toms where it is a very important predator of bivalve 

 mollusks. Juvenile specimens are occasionally encoun- 

 tered in fish stomachs. 



Leptasierias spp. (Fig. 249), which represent several 

 species of the genus Leptasierias, also of the family 

 Asteriidae, are common inhabitants of the New En- 

 gland Region on sandy bottoms. These brightly, but 

 variably, colored species are of moderate size (5-10 

 cm) and in some localities are veiy abundant. Small 

 specimens are occasionally preyed upon by some spe- 

 cies of groundfish. 



Echinarachnius parma (Lamarck) (Fig. 249), the north- 

 ern sand dollar, is the most abundant urchin (class 

 Echinoidea, family Scutellidae) of the New England 

 region; it is so abundant in some localities of Georges 

 Bank that the bottom resembles a mosaic pavement. As 

 its common name implies, it is a sand dweller. Sand 

 dollars of the region are typically 7.5 cm in diameter. They 

 are a common prey of flounders, haddock and cod. 



Strongylocentrotus droebachiensis (Miiller) (Fig. 249), 

 another ubiquitous echinoid (family Strongylocen- 

 trotidea), the green sea urchin, is a hard bottom dweller 

 for whose popular roe a commercial fishery, inactive 

 since the 1930's and 1940's, is reemerging in northeast- 

 ern U.S. and Canadian waters. Size ranges from 5 cm to 

 nearly 9 cm. Haddock and American plaice prey on this 

 spiny morsel. 



Ophiura spp. (Fig. 249) comprise three species and 

 some undetermined specimens of this genus of brittle 

 stars (family Ophiolepididae) inhabiting the New En- 

 gland region; included are O. ljungmani, O. robusta, O. 

 sarsi, and unidentified species. Members of this group are 

 widely distributed and occur in most sediment types. Size 

 of the central disc ranges from 10 to 38 mm. They are 

 common in the diets of haddock and American plaice. 



Bathymetrie Distribution 



In the New England region density and biomass of the 

 major taxa generally decreased with increasing water 

 depth (Tables 11, 13; Figs. 15, 16). Crustacea was the 

 dominant component of the fauna, in terms of density, 

 in shallow and continental shelf depths, ranging from 

 1,351 to 169 individuals/m . Substantially lower densi- 

 ties occurred in waters deeper than 200 m. Annelida 

 had the next highest densities in shallow waters (719/ 

 m-') and at continental shelf depths (519-437/m 2 ). 

 Moderate numbers (241— 107/m 2 ) occurred at conti- 



