Report: Fish fauna: Evaluation tool WFD — Transition/Coastal waters (2006)»

“The EU Water Framework Directive establishes a framework for the protection of inland surface waters, transitional waters, coastal waters and groundwater. The following objectives apply to above-ground waters: Achieving good environmental and chemical status by 2015; Achieving good ecological potential and good chemical status in significantly modified or artificial waters by 2015; Prohibition of deterioration; In the case of artificial and significantly modified surface waters, after careful examination of the possibilities for improvement, the designation as significantly modified water may be carried out. In these waters, or for sections of water where good ecological status cannot be restored or cannot be restored by proportionate means, and if restoration would significantly affect certain uses, such as hydropower, navigation and flood protection, it is not necessary to achieve good ecological status, but to achieve good ecological potential. The Directive defines the ‘good ecological state’ as a target that is to be achieved by 2015 (with exceptions also by 2027). Against this background, it is first necessary to assess the current status of the waters and thus to show the necessary need for action in relation to the objective of the WFD. In order to be able to carry out this first step, it is necessary to develop appropriate evaluation procedures for the quality components specified by the WFD. Against this background, this thesis has the task of developing a fish-based assessment tool for the water type ‘Transitional Waters North Sea’ (type T1/T2) which takes into account the specific requirements of the WFD. The water type “Transitional Waters North Sea” is characterised by the estuary salinity gradient and is characterised by the dynamic encounter of limnic and marine elements. It therefore forms a habitat of its own character, which also has a specific fish fauna. This own nature required a specific assessment approach for transitional waters with regard to the quality component of fish fauna. For this purpose, a multimetric evaluation method has been developed in this thesis, which covers the aspects of species spectrum, abundance and age structure of fish fauna and refers to a historical reference cenosis as an assessment benchmark. The BioConsult Schuchardt & Scholle GbR office was commissioned by the Länder Schleswig-Holstein and Lower Saxony to develop a corresponding fish-based assessment tool in December 2004. The project was coordinated by the Elbe Water Quality Centre and was accompanied by a group of representatives from the states of Schleswig-Holstein, Lower Saxony and Hamburg. [...]»