Date Awarded


Document Type


Degree Name

Doctor of Philosophy (Ph.D.)


Virginia Institute of Marine Science


Food habits of 23 species of demersal deep-sea fishes from the temperate Middle Atlantic Bight and the tropical Bahamas region are described. In addition, body composition parameters including percent water, ash, carbon, and nitrogen are discussed for 48 demersal species from these study areas. Food habits data on Bahamian species are combined with those from other studies in an attempt to describe the trophic structure of this tropical deep-sea fish assemblage. Numerical classification techniques are used to group species based upon similarity of diets. Four groups are evident, including a group which feeds largely on polychaetes, a second which feeds mainly on copepods along with other small crustaceans, a third group which feeds on small crustaceans but most heavily on mysids and amphipods, and finally a fourth group which feeds heavily on natant decapods and teleosts. Within each group a variety of taxa and feeding modes are apparent, including benthic species as well as benthopelagic species with and without swimbladders. Thus a variety of feeding mechanisms which result in similar diets are displayed by these fish assemblages. Body composition parameters are variable; however, some trends are evident. Benthopelagic species without swimbladders tend to have higher water contents and more poorly ossified skeletons than other species. In addition, percent water shows a positive correlation with depth of occurrence, but it is apparent that at all depths, species with a variety of body compositions have successfully adapted to life in the deep sea. The diets and body compositions of tropical species are compared with those of temperate Middle Atlantic Bight species in an attempt to account for taxonomic differences between the two areas. Species with high water contents appear to be more abundant in the Bahamas study area than in the Middle Atlantic Bight. Accordingly, species with relatively inactive life styles seem to be more important in the Bahamas region. Differences in trophic structure may account for other differences between the Middle Atlantic Bight and Bahamian faunas.



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