8. 



However, other species may in fact be attracted to the light 

 source, while many are probably not affected by it due to the 

 limited visual apparatus expected in organisms inhabiting 

 depths below the photic zone. 



The sled was navigated by following tracings of the two 

 pingers on a depth recorder. The pinger mounted to the sled 

 allowed determination of when the sled was in contact with the 

 bottom. The pinger on the cable showed obstacles and bottom 

 irregularities before the sled encountered them, thus allowing 

 manipulation of the sled to avoid them. 



Unfortunately, not all obstacles could be detected, so 

 the camera sled occasionally collided with the bottom. This 

 frequently occurred in areas of outcrops or steep terraine. 

 After a collision the camera sled frequently bounced off the 

 bottom, and thus photographic footage of the area was not 

 obtained. Additionally, areas of rough terraine were fre- 

 quently avoided by raising the sled above bottom. As a result 

 of these two factors the amount of hard substrate surveyed 

 was substantially reduced. Since many coral species are 

 restricted to hard substrate the data set is biased toward 

 underestimating their occurrence and abundance. Another problem 

 encountered during this survey was that the camera lens was 

 occasionally covered with mud after collisions. 



"Voucher" specimens and some sediment samples were 

 obtained using a day dredge. In sampling epi fauna dredging 



