AA.J3L3 Baltic photic sand dominated by ocean quahog (Arctica islandica)


HELCOM RED LIST Biotope Expert Team

Textual description 

Baltic photic zone bottoms with at least 90 % coverage of sand. Sand has less than 20 % of mud/silt/clay fraction (<63 µm), and the proportion of sand (grain size 0.063–2 mm) exceeds 70% of the combined gravel and sand fraction.  Biomass of infaunal bivalves dominates and is highest in the group that includes infaunal bivalves/polychaetes/crustaceans/echinoderms/insect larvae. Out of the infaunal bivalves, Arctica islandica constitutes at least 50 % of the biomass.       

Physical environment       

Substrate is sand.

Characteristic species        

Arctica islandica

Quality descriptors

Diversity, abundance and biomass of fauna.


Western Baltic sea

Correspondence with other classification systems               

HELCOM 1998:

2.5 Sandy bottoms

2.5.2 Sublittoral photic zone Level bottoms with little or no macrophyte


EUNIS 2012:

A5 Sublittoral sediment

A5.2 Sublittoral sand

A5.21 Sublittoral sand in low or reduced salinity

A5.211 Baltic level sandy bottoms of the infralittoral photic zone with little or no macrophyte vegetation


 Related Information

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

See the Biotope Information Sheet of AA.J3L3