Survey methodology for fish population assessment within Anglian water

Basic data required for the maintenance, improvement and development of inland fisheries within the Anglian Water Authority area are derived from surveys carried out since 1977. All open river systems are sampled on a 3-year cycle and basic data are obtained on species composition, density and biomass as well as year-class structure and growth rates of dominant species.
The netting and electrofishing gear and techniques used to obtain quantitative and semi-quantitative samples from rivers, drainage channels and the Norfolk Broads are described and their advantages and disadvantages discussed. The mark and recapture and multiple removal techniques employed with these methods are described and an assessment given of sampling efficiency in different situations.