Designing a methodology for surveying fish populations in freshwater lakes

This report was commissioned to review available fish survey methods and the limitations and constraints presented by the lakes within the SSSI series, to design a standardised, practical, and representative method for fish survey which could be reasonably applied throughout the SSSI lakes to achieve comparable results. The report then goes on to design a study which applies this fish survey design to a selection of SSSI lakes to ascertain whether fish are likely to be contributing to their unfavourable condition. This report has been used to inform a follow up study which seeks to apply the fish survey techniques to a range of SSSI lakes to ascertain information about their fish populations and their likely impact on SSSI condition. The report also includes a comprehensive review of fish survey methods and concludes with a recommended standardised fish survey method which can be applied consistently across different SSSIs to provide comparable quantitative results. It is expected that this methodology can be applied in subsequent fish surveys commissioned on SSSI lakes, to provide more robust and repeatable results.