272 



Fishery Bulletin 93(2), 1995 



within a dive. Most species were found across the 

 range of habitat types identified by the analysis, 

 though they might be most abundant in one specific 

 habitat. Active habitat selection (species variances 

 smaller than environmental variance) was not seen 

 for such species. Other species were found in num- 

 bers too small to allow a powerful test of active habi- 

 tat selection. Despite these qualifications, this study 

 demonstrated trends in habitat selection by slope 

 nekton and suggested hypotheses for further work. 



At both sites, habitat selection by demersal nek- 

 ton was related to numbers and types of sessile in- 

 vertebrates and to infaunal organisms that created 

 holes and mounds. These are also two of the trends 

 seen by Felley et al. (1989). They found that habitat 

 selection by demersal nekton of a sandy-bottom shelf 

 environment of the Gulf of Mexico was related to 

 presence or absence of large sessile invertebrates 

 (sponges, cnidarians, and small corals) and to pres- 

 ence or absence of holes and mounds. Habitat selec- 

 tion in that study was also related to amount of al- 

 gal cover. 



Both this study and that of Felley et al. ( 1989) were 

 based on analysis of videotapes originally recorded 

 for other purposes. There may be problems with us- 

 ing such videotapes. The submersible tracks were 

 not arranged as transects; therefore, we had to re- 

 main aware of potential sampling problems (e.g. the 

 submersible crossing and recrossing a particular 

 area, which did not occur on these videotapes). Sam- 

 pling bias might result from the conditions under 

 which we collected data. We had to stop collecting 

 data when the submersible stopped, when it moved 

 away from the substrate, or when it traversed areas 

 of gullies or ridges. Thus our results can be general- 

 ized to only the habitat we did sample — flat areas. 

 Despite such qualifications, archived videotapes are 

 an inexpensive source of data for exploration of ques- 

 tions relating to distribution patterns in deep-sea 

 organisms. Such patterns are difficult to study in the 

 deep sea (Gage and Tyler, 1991). By using archived 

 videotapes, hypotheses can be developed, utility of 

 specific sampling systems assessed, and improve- 

 ments in methods recommended. We feel that con- 

 sistent collection and archiving of video transects is 

 important for extending the usefulness of submers- 

 ible missions. 



Acknowledgments 



We would like to thank L. Levin, T Schaff, K. Sulak, 

 and A. N. Shepard for their comments on the manu- 

 script, insights into the dives, and identifications of 

 several invertebrate species. K. Sulak at the Atlan- 



tic Reference Centre, Huntsman Marine Science Cen- 

 tre, New Brunswick, Canada, examined still photos 

 of several species taken during these dives, and his 

 identifications form the basis of much of our demer- 

 sal nekton species section. A. B. Williams identified 

 a number of decapod crustaceans, and identifications 

 of particular fish species were provided by J. Will- 

 iams, D. G. Smith, and B. B. Collette. 



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