Starfish (Asteroidea, Echinodermata) from the Faroe Islands; spatial distribution and abundance

Abstract

“Marine benthic fauna of the Faroe Islands” (BIOFAR) is a large programme with a focus on collecting invertebrate fauna from the Faroes (62°N and 7°W). Cruises were undertaken from 1987 to 1990, and starfish (Asteroidea, Echinodermata) collected during this time were analysed. Asteroidea were sampled at ~50% of all BIOFAR stations. A Detritus sledge and a Triangular dredge proved to be the most efficient equipment, collecting over 60% of the specimens. In total 2473 specimens were collected from 20 to 1500m depth, including 41 species from 17 families and 31 genera. Henricia pertusa (O. F. Müller, 1776) group, Pontaster tenuispinus (Düben & Koren, 1846), and Leptychaster arcticus (M. Sars, 1851) showed highest relative abundance. Maximum species diversity was found at 500–700m depth, which coincides with the transition zone of water masses (North Icelandic Winter Water and Arctic Intermediate Water (NI/AI)) at approximately 400–600m depth. 63% of the species were recorded at an average-weighted depth above 600m. Two different ordination methods (detrended correspondence analysis (DCA) and nonmetric multidimensional scaling (NMDS)) gave highly consistent representations of the community structure gradients. The first ordination axis scores did not show significant relationships with any environmental variable. Biological covariates like the presence of Lophelia corals were not significantly related to ordination scores on any axis. The second ordination axis scores were significantly correlated with depth. Temperature and salinity were highly correlated (r=0.90), and both negatively correlated with depth (r=−0.69 and r=−0.57, respectively).