The coastal scleractinian coral fauna of the kermadec islands, southwestern pacific ocean

Abstract

The species diversity of the coastal scleractinian coral fauna at the subtropical Kermadec Islands attenuates southwest along the island chain from 17 hermatypic (zooxanthellate) species and 7 ahermatypic (azooxanthellate) species at the northern end (Raoul Island 29 2°S), to 2 hermatypes and 2 dhermatypes in the south (L'Esperance Rock 31 1°S) Biogeographic affinities are with other subtropical southwestern Pacific islands rather than with New Zealand The majority ot the Kermadec hermatypic species are restricted to depths shallower than 20–30 m, and encrusting growth forms predominate Hermatypic corals form scattered colonies on volcanic substrata, and there is no contemporary reef formation Coral cover is highest around Raoul Island, peaking at 20–40% of benthic cover at 1–6 m depth, with a subsidiary peak at about 15–25% of benthic cover between 18 m and 25 m depth at some sites Hermatypes form less than 1% of benthic cover around islands further south in the group Fermadec coastal ahermatypic species are largely restricted to caves and overhangs The asteroid Acanthaster planet is recorded from Raoul and Macauley Is It is common at Raoul, and is evidently an important modifier of hermatypic coral communities there. © 1999 Taylor and Francis Group, LLC.