Journal of the Marine Biological Association of the UK



Distribution, diversity and abundance of epibenthic fauna in the North Sea


Simon  Jennings a1a2, John  Lancaster a3, Andrew  Woolmer a3 and John  Cotter a2
a1 School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ
a2 Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory, NR33 0HT
a3 School of Biological Sciences, University of Wales, Swansea, SA2 8PP

Abstract

The assemblages of attached and freeliving epibenthic species in the North Sea are described, based on analysis of samples collected with a small beam trawl. Clustering of survey sites based on the presence or absence of attached species indicated that three regions had characteristic assemblages: the northern North Sea, the central North Sea from 55 to 57°N and the southern North Sea. Clustering of sites based on counts of free-living epibenthic species also revealed that the sites formed three major groups but these corresponded to regions in the north-east North Sea, the northern and western central North Sea and the southern and eastern central North Sea. Species which contributed most to the similarity within and dissimilarity between groups were identified. The environmental factors which best accounted for the grouping of sites were depth, winter temperature and the temperature difference between winter and summer for attached species and depth and the temperature difference between winter and summer for free-living species. The species richness of attached and free-living epibenthic species was higher in the central and northern North Sea than in the south. The number of abundant (Hill's N1) and very abundant (Hill's N2) free-living species also increased from south to north.