AB.E1F1 Baltic aphotic shell gravel dominated by vase tunicate (Ciona intestinalis)


HELCOM RED LIST Biotope Expert Team

Textual description 

Baltic aphotic bottoms at least 90 % coverage of shell gravel. Epibenthic chordates cover at least 10%of the seabed and more than other perennial attached erect groups. Out of the epibenthic chordates, vase tunicate constitutes at least 50 % of the biomass.

Physical environment       

Substrate is shell gravel.

Characteristic species        

Ciona intestinalis


Known from German waters in the Baltic Sea

Correspondence with other classification systems               

HELCOM 1998:

2.6 Shell gravel bottoms

2.6.1 Aphotiz 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

A5.115 Baltic shell gravel bottoms of the aphotic zone

 Related Information

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

See the Biotope Information Sheet of AB.E1F1