AA.E1E1 Baltic photic shell gravel dominated by Mytilidae


HELCOM RED LIST Biotope Expert Team

Textual description            

Baltic photic bottoms at least 90 % coverage of shell gravel. Epibenthic bivalves cover at least 10 %of the seabed and more than other attached erect groups. Out of the apibenthic bivalves Mytilidae constitutes at least 50 % of the biomass.

Physical environment       

Substrate is shell gravel.

Characteristic species        

Mytilus spp., Modiolus modiolus

Anthropogenic threats     

Increase in atmospheric CO2 (Ocean acidification)

Correspondence with other classification systems               

HELCOM 1998:

2.6 Shell gravel bottoms

2.6.2 Shell gravel bottoms in sublittoral photic zone

HELCOM 2007:

Shell gravel bottoms

  • habitat under threat and/or in decline in all areas of occurrence: The Southern Baltic Proper, The Gulf of Gdansk, Bay of Mecklenburg, Kiel Bay, Little Belt, Great Belt, The Sound, Kattegat

EUNIS 2012:

A5 Sublittoral sediment

A5.1 Sublittoral coarse sediment

A5.11 Infralittoral coarse sediment in low or reduced salinity

A5.113 : Baltic shell gravel bottoms in the infralittoral photic zone

OSPAR list of threathened biotopes:

Modiolus modiolus beds

  • Habitat occurs in the OSPAR Region II (including Kattegat) and is listed threatened and/or declining in this region