Growth and reproductive traits of deep-sea pen Anthoptilum murrayi Kölliker, 1880, from Iceland (North Atlantic)

ABSTRACT Sea pens (Octocorallia: Pennatulacea) constitute one of the most important structural species in soft bottom benthic communities. Most pennatulacean species are deep-water organisms inhabiting depths from 200–6000 m. Among these deep-sea pens, a representative set of colonies from the northeastern Atlantic Anthoptilum murrayi Kölliker, 1880 was collected thanks to the BIOICE research surveys. In this study, 18 colonies of A. murrayi were used to acquire information on essential biological traits such as age and growth rates. Our results showed that the colonies collected ranged between 6–17 years, with a diametric growth rate between 0.10–0.17 mm year−1 and a linear growth rate between 14.97–15.75 mm year−1. Moreover, the number and diameter of oocytes per polyp (PRF, ERF), and the reproductive effort at the colony level (PRE, ERE) were determined. These values were compared between colonies of different sizes and within each colony. The largest observed diameter was 1179 μm for oocytes and 711.3 μm for spermatocysts. Both approaches (growth and reproduction) were correlated, indicating that a given large A. murrayi colony (∼300 mm) might be ∼17 years old and contain >7000 oocytes, from which possibly about 2000 oocytes (∼27%) would be spawned per year.