ABSTRACT 



The abundance and distribution of the epibenthic and 

 coral fauna of the mid and north Atlantic continental margin 

 was studied by reviewing photographs from submersible dives. 

 Particular emphasis was placed on the canyon areas. The depths 

 covered ranged from 100 meters to 3200 meters. Three general 

 faunal zones were identified. The shelf and shelf -break pro- 

 vince had high faunal densities and was dominated by crustaceans 

 and fish. The mid slope region had lower faunal densities and 

 was dominated by fish. The lower slope was characterized by 

 high faunal densities and was dominated by echinoderms. This 

 pattern, though consistent on the slope, was somewhat different 

 in the canyons. Higher faunal densities, particularly of filter 

 feeding corals and sponges, attest to the greater substrate 

 variability and nutrient enrichment of the canyon areas. 



Results of community analysis yielded no discernable 

 cohesive assemblages within our study area. Rather the results 

 indicated that the dominant species are independently distributed 

 with their ranges overlapping in some areas and not in others. 

 On the whole, canyon assemblages tended to be more diverse in 

 terms of trophic types. Some species tended to have discrete 

 depth ranges, while others had very broad depth ranges. The 

 fauna exhibited a pattern of gradual species replacement with 

 increasing depth. Also noted was the tendency of some species 

 to emerge with increasing latitude. This observation could be 

 the result of a variety of environmental parameters. Our 



