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 lim- ited depth ranges. Among other benthic megafauna, Crus- tacea 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.