AB.A1I1 Baltic aphotic rock and boulders dominated by barnacles (Balanidae)


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 crustacea cover at least 10%of the seabed and more than other perennial attached erect groups. Out of the epibenthic crustacea, barnacles constitute at least 50 % of the biomass.

Physical environment       

Substrate is rock and/or boulders. Depth is typically from 0 to 20 meters. Appears in all wave exposure classes. Salinity approximately >3 psu.

Characteristic species        

Amphibalanus improvises, Balanus crenatus, Semibalanus balanoides

Quality descriptors

Diversity, abundance and biomass of fauna


Kattegat and Belt Sea

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