Performance Assessment of a Draft European Standard for Sampling Lake Fish Using Hydroacoustics

Hydroacoustics is a valuable tool for the assessment of fish populations because it enables substantial volumes of water to be sampled non-invasively, cost-effectively and potentially consistently. However, it is highly technical and operators must select from various options before, during and after surveys. In Europe, a CEN (European Committee for Standardisation) standard for sampling fish with mobile hydroacoustics has been under development since 2006 and is approaching the publication stage. Recently, the European Commission has mandated that such methodological standards must be validated through ‘inter-laboratory’ comparisons. Results are presented from the first such inter-laboratory comparison of the hydroacoustics standard conducted on the lake of Windermere (U.K.) in late autumn 2011. Six teams from five countries conducted day and night vertical surveys using three manufacturers’ models of split-beam echo sounders operating at 70, 120, 200 or 400 kHz. All aspects of the surveys were compliant with the provisional CEN standard, but teams operated their systems and processed resulting data using a variety of software according to the normal practice in their home countries and institutions. Abundance and biomass estimates are compared, and the precision of hydroacoustic estimates generated within the broad constraints of the standard are discussed.