AB.B1E4 Baltic aphotic hard clay dominated by Astarte spp


HELCOM RED LIST Biotope Expert Team

Textual description 

Baltic aphotic bottoms at least 90 % coverage of hard clay. Epibenthic bivalves cover at least 10% of the seabed and more than other perennial attached erect groups. Out of the epibenthic bivalves, Astarte spp.constitutes at least 50 % of the biomass.

Physical environment       

Substrate is hard clay. Occur at high energy exposure areas.

Characteristic species        

Astarte spp.


Known from German waters in the Baltic Sea

Correspondence with other classification systems              

HELCOM 1998:
2.3 Hard clay bottoms
2.3.1. Aphotic zone

 Related Information

This biotope has been listed as Endangered (EN) in the HELCOM Red List of Baltic Sea biotopes and habitats.

See the Biotope Information Sheet of AB.B1E4