Research and analysis

Semi-quantitative methods for fisheries classification

A project which has been carried out to evaluate the use of semi quantitative methods for fish stock assessment for use in the Fisheries Classification Scheme.

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This report discusses the various approaches to calibrating semi-quantitative methods, and critically assesses a number of regional calibration exercises undertaken by the Environment Agency and its predecessors. Three areas for improving these methodologies are identified: 1) a correction for different types of river habitat, 2) the assessment of classification errors and 3) a refinement of the statistical-procedures used.