AB.E3X Baltic aphotic shell gravel characterized by mixed infaunal macrocommunity in coarse and well sorted shells and shell fragments


HELCOM RED LIST Biotope Expert Team

Textual description            

Baltic aphotic bottoms with at least 90 % coverage of shell gravel. Macroscopic infauna present, no epibenthic macrofauna. The shell gravel mainly consists of large shells and coarse shell fragments from several different species of clams and mussels.

Physical environment       

Substrate is shell gravel. Depth below approximately 20 m.Appears mostly in high energy exposure areas.

Mapping advise (habitat delineation, identification, similar types)             

Only for biotopesoccuring in Kattegat andthe most southern parts ofthe Baltic Sea (Mytilus shell gravelin Northern Baltic Sea, shouldbe classified AB.E1E1)

Geographic range               

Southern part of Baltic Sea

Anthropogenic threats     

Increase in atmospheric CO2 (Ocean acidification)

Correspondence with other classification systems               

HELCOM 1998:

2.6 Shell gravel bottoms

2.6.1 Aphotic 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

A5.115Baltic shell gravel bottoms of the aphotic zone