A-19 



diagramatic representation of the numerical percentage of the 

 fauna accounted for by these groups. The most obvious pat- 

 tern is the increasing dominance of echinoderms with depth. 

 The shallow fauna is generally composed of crustaceans, fish 

 and a variety of other taxa . The middle depth fauna is 

 dominated by fish, while echinoderms are the major component 

 of the deeper fauna. 



These results are consistent with the findings of 

 Haedrich, Rowe and Polloni (1975) and Grassle et al., (1975). 

 The higher nutrients of the shelf and upper slope allow this 

 region to support a greater variety of trophic types. Fish 

 and crustaceans are large mobile predators and scavengers, 

 while some of the other shelf fauna are filter feeders. The 

 deeper slope environment has a lower sedimentation rate and 

 is characterized by a predominance of deposit feeding 

 echinoderms. 



The trend of replacement of faunal constituents with 

 depth is best seen in slope areas, such as is shown in Figure 

 C2 for the slope south of Baltimore Canyon. The relative 

 proportion of the major taxa are presented for 50-meter depth 

 intervals. ALVIN dive 765 covered depths ranging from 200 to 

 450 meters. Crustaceans, such as a species of Munida and 

 Canoer borealis , dominated the fauna from 200 to 300 meters. 

 The quill worm Eyalinoeaia avtifex was the dominant species 

 seen between 300 to 450 meters. This species appears to have 

 a rather patchy distribution and is found in exceedingly high 



