270 



Fishery Bulletin 93(2), 1995 



as 



3 



■o 



> 



C 



bution of some species in the assemblage. 

 In this way, we attempted to move from our 

 view of the environment to a view more con- 

 cordant with that of the species that live there. 



Our view was molded by the environmen- 

 tal variables we measured and the species 

 distributions we observed. These high- 

 lighted differences between the Cape 

 Hatteras and Cape Lookout sites, as well 

 as differences between dives at a site. In all 

 dives, the benthic environments included in 

 this analysis had soft substrate, with vis- 

 ible epifauna and evidence of infauna (holes, 

 mounds). Differences between the two dive 

 sites were seen in the species composition 

 and in the spatial distribution of these spe- 

 cies. There were some depth-related pat- 

 terns in species occurrence at the Cape 

 Hatteras location (Cape Lookout dives were 

 all at similar depths). 



Density of organisms differed greatly be- 

 tween Cape Hatteras and Cape Lookout. 

 Biota was much more dense at Cape 

 Hatteras. Summing all demersal nekton, 

 anemones, gastropods, and crinoids in each 

 interval, we found that Cape Hatteras dives 

 had a mean of 29.0 organisms per interval, 

 whereas Cape Lookout dives had a mean of 

 4.6 organisms per interval. At Cape Hat- 

 teras, dives 2623, 2627, 2629, and 2630 av- 

 eraged 24.3, 48.7, 23.0, and 5.1 organisms 

 per interval, respectively. At Cape Lookout, 

 dives 2619, 2620, and 2621 averaged 4.2, 

 4.9, and 5.0 organisms per interval, respec- 

 tively. Schaff et al. (1992) found density of 

 biota at the Cape Hatteras site to be much 

 higher than at other slope localities, includ- 

 ing the Cape Lookout site. They related the 

 high density of biota at Cape Hatteras to 

 nutrient enrichment due to an interaction 

 between the complex topography of the area 

 and upwelling currents. 



Distribution patterns of sessile epifauna 

 differed at the two sites. At Cape Hatteras, 

 ophiuroids, crinoids, and small anemones 

 showed evidence of clumped distributions. 

 Large anemones showed a clumped distri- 

 bution in dive 2629. There was no evidence 

 of clumped distributions for any sessile or- 

 ganisms at Cape Lookout. 



At Cape Hatteras, some species were re- 

 stricted to particular depths. Zonation by depth has 

 been documented for slope megafauna (Gardiner and 

 Haedrich, 1978; Rowe and Haedrich, 1979; Hecker, 

 1990a). The eel and the red deepsea crab were found 



Scorpaenid 



03 



£ 

 c 



Shortfin squid 



Factor 1 scores 

 Figure 2 



Distribution of intervals, shortfin squid, and scorpaenids on an axis 

 representing epifaunal assemblages at Cape Hatteras. Variance of 

 shortfin squid scores was significantly smaller than that of intervals, 

 whereas variance of scorpaenid scores was not significantly differ- 

 ent. This axis is the same as that labeled factor 1 in Figure 1. 



almost exclusively at middle slope dives (2623 and 2627, 

 Table 3), whereas the lizardfish and Species A were 

 found mostly in the upper slope dives. Most species 

 included in the analysis were found in a range of depths. 



