Spatial Distribution of Macrozoobenthic Species

As to be expected benthic species composition varied considerably in this part of the Baltic (Table 17.1). The most western stations 010 and 012 at the Fehmarn Belt and the Mecklenburg Bight are characterized by the bivalves Abra alba and Arctica islandica and the cumacean Diastylis rathkei, whereas the area around the Darss Sill (stn. 030) were most frequently colonized by the gastropod Hydrobia ulvae, the bivalve Mytilus 

FIGURE 17.9 Development of abundance and biomass (a) and species number and Shannon diversity (b) at the monitoring station 030 (K8) in the Darss Sill area 1991-2005. The water depth is 22 m. [1996 no data exist.] 

FIGURE 17.10 Relative abundance of most dominant species at station 030 (Darss Sill. C in Fig. 17.1) during the past 15 years. [1996 no data exist.] 

Scoloplos armiger and the cumacean Diastylis rathkei compose dominantly the station 109 in the central Arkona Sea. Though the polychaete Bylgides sarsi is very frequent at all stations it reached only minor abundances in most years. The southern Arkona Sea (stn. 152) differs completely from the other locations. The low salinity regime allows only euryhaline species to live here. The total species number is 50 (most of them occur only sporadically) and characteristic species are both the bivalves Macoma balthica and Mytilus edulis and the polychaete Pygospio elegans. In regard to maximum biomass, also clear differences are visible. 

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