AA.A1E Baltic photic rock and boulders characterized by epibenthic bivalves


HELCOM RED LIST Biotope Expert Team

Textual description            

Baltic bottoms in the photic zone with at least 90 % coverage of rock, boulders or stones of more than 63 mm in diameter. Sessile/semi-sessile epibenthic bivalves cover at least 10 % of the seabed and more than other perennial attached erect groups.

Physical environment       

Salinity range: All; Exposure range: all, more common in exposed areas; Depth range: photic zone

Characteristic species        

Mytilus spp, Dreissena polymorpha

Quality descriptors             

Diversity, abundance and biomass of fauna associated with the mussel beds.

Geographic range               

Whole Baltic Sea

Anthropogenic threats     


Correspondence with other classification systems               

HELCOM 1998:

2.1 Rocky bottoms

2.1.1 Soft rock Sublittoral photic zone

2.1.2 Solid rock (bedrock) Sublittoral photic zone

2.2 Stony bottoms

2.2.2 Sublittoral photic zone

EUNIS 2012:
A3.4 : Baltic exposed infralittoral rock
A3.5 : Baltic moderately exposed infralittoral rock
A3.6 : Baltic sheltered infralittoral rock