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Rapport, 2017

Abundance of coastal fish key functional groups. HELCOM core indicator report

Olsson, Jens; Mustamäki, Noora; Naddafi, Rahmat; Östman, Örjan; Bergström, Lena; Lappalainen, Antti; Heikinheimo, Outi; Ådjers, Kaj; Saks, Lauri; Svirgsden, Roland; Briekmane, Laura; Ložys, Linas; Dainys, Justas; Jakubavičiūtė, Eglė; Lejk, Adam; Smolinski, Szymon; Winkler, Helmut; Schulz, Norbert; Støttrup, Josianne; Brown, Elliott John

Sammanfattning

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. midtrophic-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 2011-2015. For piscivores, good status is achieved in 24 out of a total of 29 monitoring locations, and for 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 seven 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 environmental status indicated by piscivores is hence slightly better compared to that indicated by 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 of the assessment differs across areas and regions as a result of differences in monitoring methodology as well as in some countries poor temporal and spatial coverage of monitoring due to poor financial support for monitoring. The methodological confidence is high in all areas and the confidence in the accuracy of the assessment is high in majority of the assessment units. The confidence in the temporal coverage is high in all areas except for the Latvian and Lithuanian areas, and the confidence in spatial representa bility is the highest in the Finnish 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 as sessment of these areas. In the future, in line with increasing knowledge, the indicator might undergo further development

Publicerad i

HELCOM core indicator report
2017,
Utgivare: Helcom