Age and growth of a habitat‐forming deep‐sea coral <i>Solenosmilia variabilis</i> in the New Zealand region: implications for fisheries management

ABSTRACT One of the most widespread and abundant habitat forming deep‐sea corals in the South Pacific region is Solenosmilia variabilis . The age of this species was assessed using radiocarbon content ( 14 C) on long dead, recently dead, and live branch sections of coral reef matrix sampled from the New Zealand region. Conventional 14 C colony ages (yrs BP), for the living, recently dead, and long dead samples, ranged from 803 to 1186 years (Graveyard Knolls, Chatham Rise), and 907 to 11, 694 years (Louisville Seamount Chain east of New Zealand). Overall calendar ages, ranged from 84 to 292 years, and similar linear and step‐wise growth rate data were obtained. Linear growth ranged from 0.2 to 1.3 mm/yr. From a conservative estimate of matrix height of ∼20 cm, it could take hundreds of years (∼150–660) of growth for a colony of S. variabilis to attain this height, and around ∼2000 years to build a colony diameter of 1 metre. Defining the age, growth and recovery timeframes of deep‐sea coral can inform risk assessments of the level of susceptibility to trawling activity and their potential to recover, as well as provide options for the considered management of deep‐sea habitats.