Ages and growth rates of some deep-sea gorgonian and antipatharian corals of Newfoundland and Labrador

Abstract

Using bomb-14C dating and growth ring counting methods, we calculate life spans and growth rates of six species of deep-sea corals collected at depths of between 400 and 900 m from the continental slope of Newfoundland and Labrador. Bamboo corals ( Acanella arbuscula , Keratoisis ornata ) and antipatharians ( Stauropathes arctica ) secrete concentric growth rings in their axial skeletons, which were proven to form annually for K. ornata and S. arctica. These species had the lowest radial growth rates of 33 ± 11 to 75 ± 11 μm·year–1. Primnoa resedaeformis and Paramuricea spp. had higher radial growth rates of 83 ± 6 to 215 ± 37 μm·year–1. Paragorgia arborea had the highest radial growth rate of 830 ± 120 μm·year–1. Axial growth rates ranged from 0.56 ± 0.05 cm·year–1 for a specimen of Paramuricea spp. to 2.61 ± 0.45 cm·year–1 for a specimen of Primnoa resedaeformis . Life spans ranged from 18 ± 4 years for a live-collected P. resedaeformis to 200 ± 30 years for a subfossil specimen of K. ornata. Because all of the corals were from heavily fished areas, it is likely that age distributions are biased towards smaller and younger colonies. Recovery of deep-sea corals from fishing-induced damage will take decades to centuries.