AB.A1H1 Baltic aphotic rock and boulders dominated by crustose moss animals (Electra crustulenta)


HELCOM RED LIST Biotope Expert Team

Textual description 

Baltic bottoms in the aphotic zone with at least 90 % coverage of rock, boulders or stones of more than 63 mm in diameter. Epibenthic moss animals cover at least 10%of the seabed and more than other perennial attached erect groups. Out of the epibenthic moss animals, crustose moss animals constitute at least 50 % of the biomass.

Physical environment       

Substrate is rock and/or boulders.

Characteristic species        

Electra crustulenta

Quality descriptors

Diversity, abundance and biomass of fauna.

Correspondence with other classification systems               

HELCOM 1998:
2.1 Rocky bottoms

2.1.1 Soft rock Aphotic zone
2.1.2 Solid rock Aphotic zone
2.2 Stony bottoms
2.2.1 Aphotic zone