Megafaunal composition of cold-water corals and other deep-sea benthos in the southern Emperor Seamounts area, North Pacific Ocean

Abstract

Recent developments in deep-sea surveys have revealed the widespread distribution of cold-water corals over the deep-sea floor of the world ocean. There are no reports, however, concerning the taxonomic composition of cold-water corals and other benthic megafauna in the southern Emperor Seamounts area of the North Pacific Ocean. We analyzed benthic samples collected from a research vessel during scientific surveys and by scientific observers onboard commercial fishing vessels to examine the faunal composition of cold-water corals and other megabenthos in the southern Emperor Seamounts area. Seventy-eight genera of cold-water corals were identified. Gorgonians (Alcyonacea with solid axis) occurred at high frequencies with wide vertical distribution ranges, and appeared to be the major components of habitat-forming cold-water corals in the area. Scleractinia occurred at frequencies similar to those of gorgonians, but over limited depth ranges. Among other benthic megafauna, Crustacea and Echinodermata occurred at high frequencies. The results demonstrates that the regional characteristics of deep-sea benthic megafauna in the southern Emperor Seamounts area is more similar to that near the Hawaiian Islands than those reported from Aleutian, other Alaskan, Californian and Japanese waters.