Baltic Marine Environment
Protection Commission

Benthic Community Species Distribution and Abundance


The programme topic covers monitoring of benthic ecosystem elements. Monitoring is focused on biological aspects and selected species, however information on physical and chemical parameters such as substrate type, grain size, amount of organic matter, temperature, salinity and oxygen/hydrogen sulphide are also included.

Subprogramme: Hardbottom species

The hard-bottom monitoring is predominantly done in coastal waters, where the monitoring concept has been developed for the EU WFD. However, in some countries hard-bottom monitoring is also targeted for the EU Habitats Directive. The monitoring includes mainly macroalgae, but in some areas also blue mussels.

The HELCOM core indicator ‘Population structure of long-lived macrozoobenthic species‘ is linked to this sub-programme as it includes size distribution of hardbottom dwelling blue mussels. The pre-core indicator ‘Lower depth distribution limit of macrophyte species’ is also linked, as macroalgae are an essential part of photic hard bottoms.

Subprogramme: Softbottom fauna

The soft-bottom macrofauna has been monitored in the Baltic Sea since 1960s. The monitoring uses the HELCOM COMBINE methods in the offshore areas, while slightly modified methods have been developed for the coastal waters for EU WFD monitoring purposes.

The HELCOM core indicators ‘State of the soft-bottom macrofauna communities‘, measuring Benthic Quality Indices (BQIs), and Population structure of long-lived macrozoobenthic species‘, measuring size distribution of species of burrowing bivalves, are linked to monitoring being carried out under this sub-programme.

Subprogramme: Softbottom flora

Monitoring of the soft-bottom vegetation includes mainly eelgrass monitoring, but also charophytes and some freshwater plant species, such as Potamogetonspp., have been included in the monitoring and in some countries the entire species assemblage is being monitored along transects. The monitoring focuses on coastal waters and various national indicators have been developed for the EU WFD assessments. 

The HELCOM pre-core indicator ‘Lower depth distribution limit of macrophyte species’ is linked to monitoring under this sub-programme as representative soft bottom species might become included.

Responsible HELCOM Subsidiary Bodies

State and Conservation

Contact information: HELCOM Secretariat