11. 



"voucher" specimens and the background information collected 

 during the historical survey greatly helped to achieve this 

 end. 



A major disadvantage of using underwater photographs to 

 assess epibenthic faunal abundances is that biases may be 

 created by the mere presence of the camera sled and its lights, 

 For instance it has been noted that some fish are attracted to 

 disturbances of the bottom, possibly to feed on the infauna 

 exposed by displacement of sediment. Study of photographs 

 would then tend to overestimate the abundance of these species, 

 The abundances of other organisms, such as the large crab 

 Gevyon qu-inquedens and various fish are underestimated because 

 they obviously try to avoid the path of the camera sled. 

 Nothing could be done to alleviate these biases, because it 

 is impossible to determine which organisms are there because 

 of the presence of the sled or what organism has caused a 

 dust cloud that may be seen in a photograph. Another bias 

 which could not be compensated for is that the habitat of some 

 organisms, such as burrowers or ones that hide beneath rocks, 

 precludes an accurate assessment of their abundances because 

 they are rarely out on the substrate and thus are not seen in 

 the photographs. The most obvious of these is the lobster 

 Homarus amerioanus which was seen only four times throughout 

 this survey. 



