Growth and longevity of New Zealand black corals

Deep-sea corals are an important component of benthic ecosystems, but are potentially very vulnerable to ecological disturbance due to their extreme longevity and slow growth rates. Among the slowest growing genera are the ‘Black Corals’ (Family Antipatharia), which can have lifespans of millennia. The waters around New Zealand contain a variety of black corals, including species that grow at shallow depths in the southern Fjords. However, while growth rates in black corals have been reported for many other parts of the world, New Zealand's black corals have received little attention. Here we present a series of high-resolution radiocarbon dates for coral colonies of the genera Antipathella, Leiopathes and Antipathes. Our results illustrate some corals have lifespans of up to 3000 years and slow but highly variable growth (averaging 10–100 μm/yr) for genera Leiopathes and Antipathes and fast growth (averaging 2–3 cm/yr) for genera Antipathella, with no obvious regional variability in growth rates over time. Our results are broadly consistent with other black coral growth rate studies, and reinforce that New Zealand's black corals likely have low resilience to any disturbance.