Fish (workpackage 3.4)
Workpackage 3.4 aims at developing fish based community indicators reflecting the impacts of changes in water level fluctuations and eutrophication on ecological quality in lakes. Both single and multi-metric indices will be developed and tested on independent datasets. The composite metrics will include, for instance, species composition, size distribution and functional traits. The specific objectives of Workpackage 3.4 are:
- to develop fish based metrics in different geographical regions of Europe,
- to undertake uncertainty estimations on gill net fishing and
- to improve fish survey methods towards specific lake types by comparing the different fish sampling methods (gill net and hydroacoustics).
The development of metrics is based on standardised gill net samples performed in approximately 1,800 lakes across Europe. The metrics are tested on data from the new field campaigns carried out between 2009 and 2010 in 25 lakes in Norway, Sweden, England, Finland, Estonia, Poland, Germany, Denmark, France and Italy (including lakes sampled during the WISER field campaign). Sampling was carried out using both gill netting and hydroacoustics.
Oucome and products
In connection with one of the field campaigns, a workshop was held in order to calibrate sampling methodology and sample handling. The field campaign will be finished in France and Italy in 2010. A first deliverable on the characteristics of fish communities in respect to climate change has been reported, and a second deliverable on fish communities in Europe in respect to eutrophication pressures will be delivered in autumn 2010. Metrics will be developed for all geographical regions. However, focus will be on the Nordic and the Central Baltic regions providing the highest data availability.
Relevance for end-users and wider policy
Fishery activities in Italy involved stakeholders such as provincial and regional authorities, fishing associations, wildlife protection associations and local fishermen holding fishing rights. The development of preliminary common metrics facilitates the work of Geographical Intercalibration Groups, to which workpackage 3.4 has a close contact. The estimation of uncertainty related to gill net sampling results will help set realistic boundaries for ecological status, in particular between good and moderate status.