Swallowers (Chiasmodontidae, Scombriformes) of The Gully Marine Protected Area, in the northwest Atlantic

A collection of swallowers (Chiasmodontidae) was examined in exploration of a contested specific distinction between Chiasmodon niger and C. harteli. The specimens had been taken during four midwater-trawl surveys in The Gully, a submarine canyon and Marine Protected Area (‘MPA’) off the coast of Nova Scotia. Vertebral counts, the principal feature proposed for distinguishing the species, were derived from skeletal images prepared from computed tomography scans. All specimens available for study resembled the description of C. harteli but their morphology was more varied than previously supposed. In addition, the species’ distribution within The Gully was described and the chiasmodontid component of the MPA’s biodiversity established, including the presence of Kali indica – a new record for Canada’s Atlantic waters.