58. 



survey was the small shrimp that is very common in this area. 



In some places in the axis of the canyon the results 

 obtained with ALVIN and "Cheep Tow" are very similar. In 

 one area between 1500 and 1600 meters the dominant taxa in 

 both surveys were fish. However, slightly further up the 

 axis, within the same depth interval, tv7o corals Desmophyllum 

 oristagalli and" Anthomastus agassizii comprised more than 60% 

 of the fauna surveyed by ALVIN. These corals are restricted 

 to hard substrates and were very common on the outcrops and 

 numerous talus blocks found along the sides of the axis. 

 Slightly deeper, between 1700 and 1800 meters in the relatively 

 flat axis of the canyon, comparable coverage was obtained 

 using both survey methods. Interestingly, the results are 

 remarkably similar in both the types of fauna seen and in 

 their absolute abundances. Ophiomusium lymani accounted for 

 77% of the total fauna surveyed by both the camera-sled and 

 ALVIN. The two techniques gave faunal densities of 2 53 and 

 244 individuals per 100 m^ respectively. The major difference 

 between the two methods was that 16% of the fauna surveyed 

 by camera-sled was composed of the coral Pennatula aauleata^ 

 while the corals seen in the ALVIN photographs were Anthomastus 

 agassizii f Pavamuviaea grandis ^ Desmophyllum avistagalli 

 and Distiohoptilum graoile. This discrepancy is probably a 

 reflection of the fact that the ALVIN dive track followed the 

 outcrops along the side of the axis while the camera-sled was 



