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.

First deep-sea Hamigera (Demospongiae: Porifera) species associated with Cold-Water Corals (CWC) on antipodal latitudes of the world

“…Yet, despite their listing as VMEs, and the acknowledgement of CWC being reservoir of biodiversity (OSPAR commission 2010), our current knowledge regarding its associated fauna is still fragmentary. Furthermore, our knowledge of CWC associated fauna greatly varies greatly across the globe, with most studies on CWC associated fauna concentrating on North Atlantic and Caribbean waters (Henry & Roberts, 2017), with studies outside this area being fare more scarce (Etnoyer & Morgan, 2005;Baco, 2007;Miyamoto et al, 2017). Specifically, L. pertusa reefs along the Atlantic and Mediterranean waters have been intensively explored during the past years (e. g. Jensen & Frederiksen, 1992;Longo et al, 2005;Schroeder et al, 2005;van Soest et al, 2007;Buhl-Mortensen et al, 2010;Taviani et al, 2017;Bertolino et al, 2019b;Corbera et al, 2019), revealing over 1.300 associated species within CWC reefs (Roberts et al, 2006).…”

Primnoidae (Octocorallia: Calcaxonia) from the Emperor Seamounts, with Notes onCallogorgia elegans(Gray, 1870)

“…The Aleutian Islands and the seamounts of the Gulf of Alaska, only a slightly greater distance to the north than the Hawaiian Islands are to the southeast, also have a rich primnoid fauna [e.g., 19 species off the Aleutians (Cairns 2011) and five different species from the deep seamounts in the Gulf of Alaska (Cairns and Baco 2007)]. However, no species are held in common between the Emperor Seamounts and this more northerly region, a finding recently reported by Miyamoto et al (2017).…”

“Firefly” of the Submarine Mountains: New Data on Physiculus cynodon (Moridae, Teleostei) from Emperor Seamounts and Northwestern Hawaiian Ridge

“…Physiculus cynodon has never been a targeted species on the seamounts under study. It has primarily been bycatch associated with the main commercial species Pentaceros wheeleri and Beryx splendens [33,57,59]. The maximum trawl fishing efforts on the Emperor Seamounts were concentrated on Jingu, Lira, Koko, Yuryaku, Kammu, Colahan, and C-H seamounts [19,[60][61][62].…”