We developed a fish fauna quality classification model
The WFD requires that surface water bodies are classified according to ecological status and that goals are set for improving or maintaining the quality of water bodies in order to achieve good ecological status (or good ecological potential for heavily modified water bodies). As part of this, fish fauna quality is classified and the consistency of approaches and results across Europe is checked through a process of intercalibration. Scotland and Northern Ireland Forum for Environmental Research (Sniffer) appointed HR Wallingford to develop a tool for classifying fish quality in rivers in Scotland, Northern Ireland and the Republic of Ireland to meet WFD requirements for classification and intercalibration.
The project developed a statistical model to extend the Environment Agency’s existing Fisheries Classification Scheme FCS2 method (which was previously applied to England and Wales). The work we carried out was to enhance the FCS2 method, take into account new data formats and provide the classifications for Scotland, Northern Ireland and the Republic of Ireland. Our enhanced model is implemented through code written in the statistical package R, linking with WinBUGS software to carry out part of the analysis. For a single species and sites, the calculated Ecological Quality Ratio (EQR) (the observed value of the site compared to its value if it were undisturbed) is based upon the probabilistic comparison of observed fish counts with predictions made under reference condition. The EQR for multiple species and sites are then combined to give a single EQR with which to classify a water body. The main model enhancements were to include multiple pass data, take account of natural barriers and consider the age classes of species where data is available.
The output from this project is a practical fish fauna quality classification model that conforms to the WFD requirements. The model has been used to classify fish fauna quality in rivers across Scotland, Northern Ireland and the Republic of Ireland. This project has provided WFD classifications for the fish survey databases, and the classification of new surveys in the future can be done using the same tool.
Since the completion of this study for Sniffer, HR Wallingford has been working for the Environment Agency to further develop FCS2 for updating the classification of fish fauna quality for England and Wales. This work is ongoing.
HR Wallingford brought excellent statistical expertise to this work on fish classification.Sniffer