HELCOM RED LIST Biotope Expert Team
Baltic bottoms in the photic zone with at least 90 % coverage of rock, boulders or stones of more than 63 mm in diameter. Epibenthic bivalves cover at least 10%of the seabed and more than other perennial attached erect groups. Out of the epibenthic bivalves Mytilidae constitute at least 50 % of the biomass.
Substrate is rock and/or boulders. Depth is typically from 5 to 20 meters. Appears in all wave exposure classes. Salinity must be at least 5 psu.
Mytilus spp. and Modiolus modiolus
Amount of sediment and epiphytic annual algae. Diversity, abundance and biomass of fauna.
Baltic Sea up to the Quark in the North.
HELCOM 1998: 184.108.40.206.1 Sublittoral level soft rock bottoms with little or no macrophyte vegetation 220.127.116.11.1 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
OSPAR list of threathened biotopes:
Modiolus modiolus beds
Habitat occurs in the OSPAR Region II (including Kattegat) and is listed threatened and/or declining in this region
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