The Pennatulid Kophobelemnon stelliferum (Cnidaria: Octocorallia) in the Porcupine Seabight (north-east Atlantic Ocean)

• Published in: Journal of the Marine Biological Association of the United Kingdom
• Main Authors: Rice, A.L., Tyler, P.A., Paterson, G.J.L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1992
• Subjects: Aquatic Science; Porcupine Seabight; North East Atlantic
• Online Access: http://dx.doi.org/10.1017/s0025315400037796; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0025315400037796

The upper bathyal sea-pen Kophobelemnon stelliferum extends to depths of about 1600 m in the Porcupine Seabight, to the south-west of Ireland, but is rare below about 1150 m. Photographic data suggest that the species attains numerical abundances of more than 2 m −2 and a wet weight biomass of at least 4 g m −2 . The highest densities, however, do not necessarily correspond to the highest biomass values since there is a clear depth-related change in population structure. The largest sea-pens are restricted to the deeper parts of the bathymetric range of the species. There is also a marked change in the growth form at a total colony length of about 250 mm, with larger colonies having relatively more polyps than smaller ones. The sexes are separate in Kophobelemnon stelliferum and the sex ratio of colonies is about 1:1. The maximum oocyte diameter is about 800 μm, but there is no evidence of seasonal reproduction by this pennatulid in the Porcupine Seabight.