This pre-core indicator and its threshold values are yet to be commonly agreed in HELCOM. The indictor is included as a test indicator for the purposes of the 'State of the Baltic Sea' report 2018, and the results are to be considered as intermediate.
Monitoring of cyanobacteria in the Contracting Parties of HELCOM is described on a general level in the HELCOM Monitoring Manual in the sub-programme phytoplankton species composition, abundance and biomass.
Specific monitoring guidelines are under development with the aim to be included in the HELCOM Monitoring Manual at a later stage.
The monitoring activities relevant to the indicator that are currently carried out by HELCOM Contracting Parties are described in the HELCOM Monitoring Manual Sub-programme sub-programme phytoplankton species composition, abundance and biomass
The temporal and spatial coverage of the satellite remote sensing data used can be considered high in the open sea areas as well as in the outer coastal assessment areas of the Baltic Sea.
Cyanobacterial biomass monitoring takes place according to the national monitoring programmes.
For remote sensing data, annually at least 30 daily spatial aggregates from valid bloom observations in an assessment area should be applied from the period between June 20th – August 30th in order to derive the annual bloom characteristics information. The compilation of observations is expected to be distributed spatially within the assessment unit in a non-biased way.
For biomass data, at least one sample per month has to be available to allow the calculation of seasonal averages. This precondition could also be fulfilled by pooling nearby stations.