AA.A1C4 Baltic photic rock and boulders dominated by kelp


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. Perennial attached algae covers at least 10 % of the seabed, and more than other perennial attached erect groups. Out of the perennial attached algae kelp constitutes  at least 50 % of the biovolume.

Physical environment             

Salinity range: >11 psu; Exposure range: all, more common in exposed areas; Depth range: photic zone usually from about 2 to 10 meters

Substrate is rock and/or boulders. Depth is typically from 2 to 10 meters, also deeper in areas with clear water. Appears in all wave exposure classes.

Characteristic species        

Saccharina latissima, Laminaria digitata

Quality descriptors             

Lower limit of vegetation, amount of epiphytic algae

Geographic range               

Kattegat, the Sound and Belt Sea

Anthropogenic threats     


Correspondence with other classification systems               

HELCOM 1998: Sublittoral level soft rock bottoms dominated by macrophyte vegetation Sublittoral level stony bottoms dominated by macrophyte vegetation

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