200 



NOAA Technical Report NMFS 140 



about 25 mm and arm lengths over 12 cm, to small 

 specimens of Amphipholis and Ophiura, with disc dia- 

 meters of less than 2 mm and arms 10 mm long. 



The coloration exhibited bv ophiuroids in our samples 

 was varied. Some genera, such as Ophiura and 

 Ophiomusium, were uniformly whitish or light gray. Oth- 

 ers were more colorful because of their mottled pat- 

 terns of contrasting hues, including dark red, pink, 

 brown, and orange. Among the more brightlv colored 

 genera were Ophiopholis, Amphiura, and Ophioscolex. 



Ophiuroids obtain their food bv a variety of different 

 feeding methods; feeding types represented in our 

 samples were carnivores, detritus feeders, filter feeders, 

 and omnivores. A large share of the New England spe- 

 cies generally combines the ingestion of bottom mate- 

 rial with selective carnivorous feeding. The diet thereby 

 consists ol detritus, diatoms, and other small-size foods, 

 as well as polychaete worms, crustaceans, bivalve mol- 

 lusks, and other similar upes of organisms. Brittlestars. 

 in turn, are preyed upon bv other echinoderms, but 

 mosi significantly by demersal fishes. 



Ophiuroidea occurred in 487 samples (45% of the 

 total). Their density averaged 44.2/m 2 and their biom- 

 ass averaged 3.26 g/m (Table 5). 



Geograph ic Distribution 



Brittlestars occurred over approximately three-fourths 

 of the study area (Fig. 220). Their average density over 

 most of their range was between 1 and 49 individuals/ 

 m 2 . High densities (100 to 680/m 2 ) were widespread 

 along the outer continental shelf south of Nantucket 

 Shoals. Brittlestars were absent from large portions of 

 central Georges Bank, Nantucket Shoals, and much of 

 the New York and New Jersey region. 



Biomass distribution of ophiuroids tended to parallel 

 their density distribution. Moderate (1—10 g/m ) and 

 large (10-80 g/m L> ) biom^sses were widespread off 

 Southern New England on the outer continental shelf, 

 and in the eastern Gulf of Maine. 



The average density of ophiuroids was moderate to 

 moderately high in all six standard geographic areas 

 (Table 6; Fig. 221). Highest average density (94/m 2 ) 



