Vendace (Coregonus albula) stock assessment in winter using a mobile echo-survey under ice

As a consequence of a local disagreement between commercial fishermen and local fishing-right owners, we estimated the size of a vendace (Coregonus albula) stock in a southern boreal lake in Finland in March 2000. We applied a mobile under-ice echo-survey and catch sampling from winter seining. The sounder with a tape recorder was placed in a shuttle and towed under ice from hole to hole with a rope. The mean fish density was 4270 fish ha–1. Vendace biomass was estimated to be ca. 36 tonnes. Commercial fishing started on a restricted scale after the completion of the assessment. The vendace yield was ca. 6 tonnes in the area during the remainder of the winter-seining season. The total winter seining catch amounted to ca. 40% of the initial vendace stock size in January 2000.