AA.I1E Baltic photic coarse sediment characterized by epibenthic bivalves


HELCOM RED LIST Biotope Expert Team

Textual description            

Baltic photic bottoms with at least 90 % coverage of coarse sediment. Coarse sediment has less than 20 % of mud/silt/clay fraction (<63 µm), and the proportion of gravel and pebbles (grain size 2–63 mm) exceeds 30% of the combined gravel and sand fraction. Sessile/semi-sessile bivalves cover at least 10 % of the seabed and more than other perennial attached erect groups.

Physical environment       

Substrate is coarse sediment. Appears in high energy exposure areas.

Characteristic species        

Mytilus spp.

Quality descriptors             

Diversity, abundance and biomass of fauna.

Geographic range               

Whole Baltic Sea

Correspondence with other classification systems               

HELCOM 1998:
2.4 Gravel bottoms

2.4.2 Sublittoral photic zone Level bottoms with little or no macrophyte vegetation

EUNIS 2012:

A5 Sublittoral sediment

A5.1 Sublittoral coarse sediment

A5.11 Infralittoral coarse sediment in low or reduced salinity

A5.111 : Baltic level gravel bottoms of the infralittoral photic zone with little or no macrophyte vegetation