ASSESSING HABITAT USE BY NEKTON ON THE CONTINENTAL-SLOPE USING ARCHIVED VIDEOTAPES FROM SUBMERSIBLES

Videotapes of the sea floor were taken from a submersible during dives at two areas on the continental slope off Cape Hatteras and Cape Look out, North Carolina, in September 1989. We counted demersal nekton, ep ifauna, and environmental features for 1-minute intervals from video t ransects. Common morphospecies of demersal nekton were identified, and multivariate analyses were performed to find environmental features t hat related to habitat use by these forms. In both areas, the ocean fl oor was extensively sculptured with holes and mounds, and both small a nd large sea anemones were commonly observed. Crinoids were seen in Ca pe Hatteras dives. Small sea anemones were much more abundant off Cape Hatteras, whereas holes and mounds were more densely distributed off Cape Lookout. Rattails, hake, and sergestid shrimp were common at both locations. Eels were extremely abundant at the Cape Lookout site, whe reas eelpouts, flounder, and lizardfish were found only at the Cape Ha tteras location. At both locations, analyses of nekton habitat choices showed that habitat selection was related to density of the holes and mounds made by infauna and to density of the epifauna, such as crinoi ds and the different types of anemones. Hake, squid, sergestid shrimp, and lizardfish showed the strongest evidence of habitat selection. An alysis of videotapes, originally recorded for other purposes, is a cos t-effective means for preliminary examination of the problems that may only be addressed by in situ observations.