This core indicator evaluates the abundance of selected functional groups of coastal fish in the Baltic Sea. As a rule, good status is achieved when the abundance of piscivores (i.e. fish that feed on other fish) is above a site-specific threshold value, and the abundance of cyprinids or mesopredators (i.e. mid trophic-level fish) is within an acceptable range for the specific site. The status of functional groups of coastal fish in the Baltic Sea has been evaluated by assessing the status of piscivores and cyprinids/mesopredators during the period 2011-2016.
Key message figure 1. Status assessment results based evaluation of the indicator 'abundance of coastal fish key functional groups', piscivores (left) and cyprinids/mesopredators (right). The assessment is carried out using Scale 3 HELCOM assessment units (defined in the HELCOM Monitoring and Assessment Strategy Annex 4). Click here to access
interactive maps at the HELCOM Map and Data Service: piscivores and cyprinids/mesopredators.
For piscivores, good status is achieved in 25 out of a total of 29 monitoring locations, resulting in good status in 13 coastal HELCOM assessment units out of the 16 that were evaluated. For cyprinids/mesopredators, good status is only achieved in 15 of the 27 monitored locations and thus in 7 of the 16 evaluated assessment units. In the locations classified as not good, the abundance of cyprinids was too high in all but one (Hiiumaa, Estonia) of the 12 locations.
The status of piscivores is hence slightly better compared to that of cyprinids. Generally, the status of piscivores is better in more northern areas compared to more central areas. For cyprinids/mesopredators, good status is not achieved in the Swedish part of the Quark and Åland Sea, in all Finnish coastal waters except for the Bothnian Bay, and in Estonian and Latvian coastal waters.
The level of confidence in the assessment differs between areas and regions due to differences in monitoring methodology as well due to lower temporal and spatial coverage of monitoring in some countries, the latter generally relating to resource availability. The methodological confidence is high in all areas and the confidence in the accuracy of the assessment is high in the majority of the assessment units. The confidence in the temporal coverage is high in all areas except for Latvian and Lithuanian coastal areas, and the confidence in spatial representability is the highest in Finnish coastal areas, but poorer in other countries.
The indicator is operational in the coastal waters of most countries bordering the Baltic Sea. For the time being, it is not applicable in some areas where coastal fish monitoring data are scarce and further studies as well as time series are needed to yield a reliable assessment. In the future, in line with increasing knowledge, the indicator might undergo further development.
The state of coastal fish communities reflects the ecological state of coastal ecosystems, as well as the effects of recreational and small-scale coastal commercial fishery activities. Changes in the long-term development of the abundance of coastal fish functional groups reflects the effects of increased water temperature and eutrophication in coastal areas, and/or changes in the level of human exploitation (fishing and habitat degradation) and natural predation pressure.
D4 Food webs
D4C2. Trophic guilds, balance of total guild abundance
HELCOM (2018) Abundance of coastal fish key functional groups. HELCOM core indicator report. Online. [Date Viewed], [Web link].
Abundance of coastal fish key functional groups HELCOM core indicator 2018 (pdf)