Reiss, H., Degraer, S., Duineveld, G. C. A., Kröncke, I., Aldridge, J., Craeymeersch, J., Eggleton, J. D., Hillewaert, H., Lavaleye, M. S. S., Moll, A., Pohlmann, T., Rachor, E., Robertson, M., vanden Berghe, E., van Hoey, G., and Rees, H. L. 2010. Spatial patterns of infauna, epifauna, and demersal fish communities in the North Sea. – ICES Journal of Marine Science, 67: 278–293. Understanding the structure and interrelationships of North Sea benthic invertebrate and fish communities and their underlying environmental drivers is an important prerequisite for conservation and spatial ecosystem management on scales relevant to ecological processes. Datasets of North Sea infauna, epifauna, and demersal fish (1999–2002) were compiled and analysed to (i) identify and compare spatial patterns in community structure, and (ii) relate these to environmental variables. The multivariate analyses revealed significantly similar large-scale patterns in all three components with major distinctions between a southern community (Oyster Ground and German Bight), an eastern Channel and southern coastal community, and at least one northern community (>50 m deep). In contrast, species diversity patterns differed between the components with a diversity gradient for infauna and epifauna decreasing from north to south, and diversity hotspots of demersal fish, e.g. near the major inflows of Atlantic water. The large-scale hydrodynamic variables were the main drivers for the structuring of communities, whereas sediment characteristics appeared to be less influential, even for the infauna communities. The delineation of ecologically meaningful ecosystem management units in the North Sea might be based on the structure of the main faunal ecosystem components.

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Sandeel abundance and sediment particle size data from 2886 grab samples collected during 14 surveys undertaken in the Wee Bankie/Marr Bank region of the north-western North Sea between 1998 and 2003 are analysed. Odds Ratio, an analysis that compares the proportion of all samples assigned to a particular sediment category, with the proportion of samples containing sandeels assigned to the same category, reveals clear patterns of either selection for, or avoidance of, seabed habitats containing varying proportions of 8 sediment particle size categories. As the proportion of Coarse Gravel, Fine Gravel, Fine Sand, Coarse Silt, Medium Silt and Fine Silt in the seabed habitat increases, sandeels show reduced selection for and increased avoidance of the habitat. Conversely, as the proportion of Coarse Sand and Medium Sand in the sediment increases, sandeels show reduced avoidance of and increased selection for the habitat. Classification Tree and Principal Components Analysis define 8 types of seabed habitat on the basis of their sediment particle size composition that vary in sandeel occupancy rate, sandeel density and the size of sandeels that occupy the habitat. Variation in sandeel density across these 8 habitat types is primarily influenced by the silt content in the sediment. Variation in the size of sandeels occupying each habitat type is mainly dictated by the coarseness of the sediment. The value of such results for the design of grab surveys intended to monitor variation in local sandeel abundance is discussed.KEY WORDS: Ammodytes marinus · Sandeel · Habitat preference · Sediment particle size Resale or republication not permitted without written consent of the publisher

The North Sea Benthos Project 2000 was initiated as a follow-up to the 1986 ICES North Sea Benthos Survey with the major aim to identify changes in the macrofauna species distribution and community structure in the North Sea and their likely causes.The results showed that the large-scale spatial distribution of macrofauna communities in the North Sea hardly changed between 1986 and 2000, with the main divisions at the 50 m and 100 m depth contours. Water temperature and salinity as well as wave exposure, tidal stress and primary production were influential environmental factors on a large (North Sea-wide) spatial scale.The increase in abundance and regional changes in distribution of various species with a southern distribution in the North Sea in 2000 were largely associated with an increase in sea surface temperature, primary production and, thus, food supply. This

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