The macrofauna of a stony sand area in the German Bight (North Sea)

Abstract

The sublittoral macrofauna of the Steingrund, a stony area east-northeast of Helgoland, was investigated from May till October 1991 using a van Veen grab and a small dredge. The diverse endo- and epifauna of the sandy bottoms, pebbles and boulders of this Saalian end moraine comprised 289 taxa, whereby the polychaetes Magelona papilhcornis, Lanice conchilega and Spiophanes bombyx dominated in terms of abundance. Species rare in the German Bight, such as the sponge Leucandra fistulosa, the sea urchin Echinus esculentus, and the sea anemone Haliplanella lineata, were also found. The two sample sets were processed separately with multivariate techniques, and differentiated on the basis of occurrence and numbers of the abundant species. The analysis of the grab samples revealed two types of the Tellina-fabula-community. These associations were differentiated by the presence of species of the coarse-sand-inhabiting Goniadella-Spisulacommunity and were related to the distribution of the grain size of the sediment. Likewise, two epifaunal assemblages were distinguished. Sandy bottoms were characterized by Ophiura albida, Liocarcinus holsatus and Pagurus bernhardus, while boulders and pebbles were covered by a varied sessile and mobile epifauna dominated by the sessile bryozoan Flustra foliacea and the mobile pantopode Aechelia echinata. Numerical density, biomass and annual production estimates are in the range of values determined for the macrobenthos of the German Bight, while annual P/B ratios mounted up to 5.