Publications

Pyle​ et al. 2016


scientific article | PeerJ | open access Open access small aa108fa7f478951c693af64a05bc4b46e6711dbb69a20809512a129d4d6b870f

A comprehensive investigation of mesophotic coral ecosystems in the Hawaiian Archipelago

Pyle​ RL, Boland R, Bolick H, Bowen BW, Bradley CJ, Kane C, Kosaki RK, Langston R, Longenecker K, Montgomery A, Parrish FA, Popp BN, Rooney​ J, Smith CM, Wagner D, Spalding HL

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Abstract

Although the existence of coral-reef habitats at depths to 165 m in tropical regions has been known for decades, the richness, diversity, and ecological importance of mesophotic coral ecosystems (MCEs) has only recently become widely acknowledged. During an interdisciplinary effort spanning more than two decades, we characterized the most expansive MCEs ever recorded, with vast macroalgal communities and areas of 100% coral cover between depths of 50–90 m extending for tens of km2 in the Hawaiian Archipelago. We used a variety of sensors and techniques to establish geophysical characteristics. Biodiversity patterns were established from visual and video observations and collected specimens obtained from submersible, remotely operated vehicles and mixed-gas SCUBA and rebreather dives. Population dynamics based on age, growth and fecundity estimates of selected fish species were obtained from laser-videogrammetry, specimens, and otolith preparations. Trophic dynamics were determined using carbon and nitrogen stable isotopic analyses on more than 750 reef fishes. MCEs are associated with clear water and suitable substrate. In comparison to shallow reefs in the Hawaiian Archipelago, inhabitants of MCEs have lower total diversity, harbor new and unique species, and have higher rates of endemism in fishes. Fish species present in shallow and mesophotic depths have similar population and trophic (except benthic invertivores) structures and high genetic connectivity with lower fecundity at mesophotic depths. MCEs in Hawai‘i are widespread but associated with specific geophysical characteristics. High genetic, ecological and trophic connectivity establish the potential for MCEs to serve as refugia for some species, but our results question the premise that MCEs are more resilient than shallow reefs. We found that endemism within MCEs increases with depth, and our results do not support suggestions of a global faunal break at 60 m. Our findings enhance the scientific foundations for conservation and management of MCEs, and provide a template for future interdisciplinary research on MCEs worldwide.

Research sites

10.7717   peerj.2475
Keywords
Meta-data
Depth range
30- 150 m

Mesophotic “mentions”
239 x (total of 12291 words)

Fields
Biodiversity Ecology Community structure Physiology Oceanography Connectivity

Research focus
Fishes Scleractinia (Hard Corals) Overall benthic (groups) Octocorallia (Soft Corals) Algae (Macro, Turf and Crustose Coralline)

Locations
USA - Hawaii

Research platforms
Remotely Operated Vehicle (ROV) Diving - Technical Open-Circuit Diving - Technical Rebreather Manned Submersible
Author profiles
Raymond Boland ( 6 pubs)
Brian Bowen ( 2 pubs)
Corinne Kane ( 5 pubs)
Randall Kosaki ( 10 pubs)
Ken Longenecker ( 2 pubs)
Anthony Montgomery ( 6 pubs)
Frank Parrish ( 7 pubs)
Daniel Wagner ( 20 pubs)
Heather Spalding ( 11 pubs)
Richard Pyle ( 17 pubs)