AA.A1F1 Baltic photic rock and boulders dominated by sea squirts (Ascidiacea)


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. Epibenthic chordates cover at least 10%, and more than other perennial attached erect groups. Out of the attached epibenthic chordates, Ascidiacea represent at least 50 % of the biomass.

Physical environment             

Substrate is rock and/or boulders.

Characteristic species              

Ascidiacea: Dendrodoa grossularia, Molgula spp.

Quality descriptors                   

Diversity, abundance and biomass of fauna.

Geographic range                     

Kattegat and Belt Sea

Correspondence with other classification systems               

HELCOM 1998: Sublittoral level soft rock bottoms with little or no macrophyte vegetation Sublittoral level stony bottoms with little or no macrophyte vegetation

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