Distribution and diet of Cyclothone microdon (Gonostomatidae) in a submarine canyon

Abstract

The primarily bathypelagic gonostomatid Cyclothone microdon, amongst the most abundant of all vertebrates, remains poorly known. We describe its diet in The Gully, a very large submarine canyon off Nova Scotia, Canada, based on the stomach contents of specimens caught by midwater trawl. In The Gully, C. microdon had a shallower distribution than in open ocean and primarily fed at mesopelagic depths. Most of its diet comprised vertically migrant calanoid copepods, while its secondary prey was conchoeciinid ostracods. Both were typical of the food eaten in other regions by its mesopelagic congeners and were consistent with the results of the only previous dietary study of C. microdon.