AUTHOR=Boland Raymond C. , Hyrenbach K. David , DeMartini Edward E. , Parrish Frank A. , Rooney John J. 

TITLE=Quantifying Mesophotic Fish Assemblages of Hawai‘i’s Au‘au Channel: Associations With Benthic Habitats and Depth

JOURNAL=Frontiers in Marine Science

VOLUME=8

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2021.785308

DOI=10.3389/fmars.2021.785308

ISSN=2296-7745

ABSTRACT=<p>Mesophotic reefs (30–150 m) occur in the tropics and subtropics at depths beyond most scientific diving, thereby making conventional surveys challenging. Towed cameras, submersibles, and mixed-gas divers were used to survey the mesophotic reef fish assemblages and benthic substrates of the Au‘au Channel, between the Hawaiian Islands of Maui and Lāna‘i. Non-parametric multivariate analysis: Non-metric Multidimensional Scaling (NMDS), Hierarchical Cluster Analysis (HCA), Multi-Response Permutation Procedure (MRPP), and Indicator Species Analysis (ISA) were used to determine the association of mesophotic reef fish species with benthic substrates and depth. Between 53 and 115-m depths, 82 species and 10 genera of fish were observed together with 10 types of benthic substrate. Eight species of fish (<italic>Apolemichthys arcuatus</italic>, <italic>Centropyge potteri, Chaetodon kleinii, Chromis leucura, Chromis verater, Forcipiger</italic> sp., <italic>Naso hexacanthus</italic>, and <italic>Parupeneus multifasciatus</italic>) were positively associated with increasing depth, <italic>Leptoseris</italic> sp. coral cover, and hard-bottom cover, and one species (<italic>Oxycheilinus bimaculatus</italic>) of fish was positively associated with increasing <italic>Halimeda</italic> sp. algae cover. Fish assemblages associated with rubble were not significantly different from those associated with sand, <italic>Montipora</italic> coral beds and <italic>Leptoseris</italic> coral beds, but were distinct from fish assemblages associated with hard bottom. The patterns in the data suggested two depth assemblages, one “upper mesophotic” between 53 and 95 m and the other deeper, possibly part of a “lower mesophotic” assemblage between 96 and 115 m at the edge of the rariphotic and bottomfish complex.</p>