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Felley, J.D. and M. Vecchione

Assessing habitat use by nekton on the continental slope using archived videotapes from submersibles.
Fishery Bulletin 93:262-273.

ABSTRACT: Videotapes of the sea floor were taken from a submersible during dives at two areas on the continental slope off Cape Hatteras and Cape Lookout, North Carolina, in September 1989. We counted demersal nekton, epifauna, and environmental features for 1-minute intervals from video transects. Common morphospecies of demersal nekton were identified, and multivariate analyses were performed to find environmental features that related to habitat use by these forms. In both areas, the ocean floor was extensively sculptured with holes and mounds, and both small and large sea anemones were commonly observed. Crinoids were seen in Cape 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, whereas eelpouts, flounder, and lizardfish were found only at the Cape Hatteras 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 crinoids and the different types of anemones. Hake, squid, sergestid shrimp, and lizardfish showed the strongest evidence of habitat selection. Analysis of videotapes, originally recorded for other purposes, is a cost-effective means for preliminary examination of the problems that may only be addressed by in situ observations.

Illex illecebrosus Illex illecebrosus
Video sequences showing shortfin squid rising off the bottom upon approach of the submersible. An individual may be seen resting on the bottom amid others that have already risen in Video 3. Squid were found significantly more often in areas with few epifauna.
Shortfin squid 1. AVI video (913 Kb) or MPEG video (516 Kb)
Shortfin squid 2. AVI video (909 Kb) or MPEG video (516 Kb)
Shortfin squid 3. AVI video (1,028 Kb) or MPEG video (574 Kb)

Bathypolypus arcticus Small octopod, probably Bathypolypus arcticus
An individual resting on the bottom. Small octopods were most often associated with objects on the bottom, including sea anemones, crinoids and gastropod shells.
Octopod 1. AVI video (1,333 Kb) or MPEG video (658 Kb)

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