51. 



amount of hard substrate available in that canyon. An 

 additional factor may be that the heavy sedimentation rate 

 in this canyon precludes large populations of these corals 

 as a result of sediment loading, such that it would be harder 

 for them to survive. 



The coral populations of the two northern canyons are 

 more similar in terms of species composition. However, on the 

 whole Oceanographer Canyon has higher concentrations of corals 

 and they are not as restricted to the axis of the canyon as 

 they are in Lydonia Canyon. The three most common corals are 

 Eunephthya ftorida^ Paramuriaea grandis and Acanthogorgia 

 armata. Figure 26 shows the abundance of these three corals 

 in Oceanographer and Lydonia Canyons. Abundances of E. flovida 

 are highest in Lydonia Canyon, with this species dominating 

 the coral population in the shallower part of the axis between 

 500 to 800 meters. The other two corals P. grandis and A.armata 

 are more common in Oceanographer Canyon. Reasons for these 

 differences are not known at this time. Of these three 

 corals only P. gvandis is not found in Baltimore Canyon. 

 This agrees with the results of the historical survey where 

 Pavamuvioea grandis was restricted to the northern part of 

 the study area. 



Coral communities 



Principal components analysis of the coral fauna was only 

 attempted for Lydonia and Oceanographer Canyons, because coral 



