Pyle et al. 2019

scientific chapter |

Fishes: Biodiversity

Pyle RL, Kosaki RK, Pinheiro HT, Rocha LA, Whitton RK, Copus JM


Fishes are an important component of coral reef ecosystems, and in comparison to other marine phyla, the taxonomy of fishes is relatively robust. Some of the earliest explorations of mesophotic coral ecosystems (MCEs) involving both submersibles and rebreather diving focused on fishes. Since 1968, over 400 publications have documented fishes on MCEs, ~75% of which were published since 2011. Most fish species inhabiting MCEs belong to families and genera typical of shallow coral reefs, and many new species remain to be discovered and described. Species richness generally peaks at a depth of 30 m and declines with increasing depth. The composition of the fish communities on MCEs includes a mixture of species restricted to MCEs and species with broad depth ranges. Patterns of species turnover and composition vary depending on geographic location, ecological characteristics, and method of study. Nearly 70% of MCE fish research has occurred within the tropical western Atlantic and Hawaiʻi. Not enough is known about global distributions to infer broad biogeographical patterns, but there seems to be higher representation by endemic species and individuals on MCEs, and the eastward attenuation of diversity of shallow Pacific reefs does not appear to apply to fishes within MCEs. Analyses of nearly 900,000 occurrence records of reef fishes at depths of 1–200 m reveal patterns of diversity that are mostly consistent with controlled studies. Future work should emphasize basic exploration and documentation of diversity in under-sampled geographic regions and hypothesis-driven studies in areas where logistics facilitate MCE research.