This report is based on experiments carried out in Lake Constance (Bodensee) in October 1983 under the auspices of the European Inland Fisheries Advisory Commission (EIFAC).
The plans for the present work were discussed at a meeting of the Steering Committee in Hamburg on 2 June 1981 by Prof. Dr. Tiews, Dr. Bagenal, Dr. Lindem, Dr. Löffler, and Dr. Tuunainen, and in Budapest on 2 June 1982, during the 12th session of EIFAC.
The exercise followed the 1980's exercise in Konnevesi (Bagenal et al., 1982) during which the number of fish and size distribution assessed by an echo sounder were compared with those based on trawl catches. The main goals of the Lake Constance exercise were to provide an example of a hydro-acoustic survey in a deep subalpine lake, and later to compare the acoustic assessment with that obtained from VP-analysis 1 determined from commercial catches. Trawling was done during the experiment mainly to identify fish species and to get additional information about the fish distribution in the Lake.
This exercise took place in the upper part of Lake Constance (Bodensee-Obersee) (Figure 1) from 23 to 29 October 1983.
The Bodensee-Obersee is a mesotropic subalpine lake at the southern border of the Federal Republic of Germany (47°N/09°E) with a surface area of 476 km2, a mean depth of 100 m, and a maximum depth of 252 m. Further limnological and fisheries details are given in Hartmann and Nümann (1977).
The participants from outside the Federal Republic of Germany were Dr. T. Lindem, Physics Institute, the University of Oslo, Norway; Mr. J. Jurvelius, Finnish Game and Fisheries Institute, Enonkoski, Finland; Dr. H. J. Meng, Seenforschungslaboratorium der EAWAG, Kastanienbaum, Switzerland; and Dr. F. Dauba, Ecole nationale supérieure agronomique, Toulouse, France.
The German personnel included Dr. E. Dahm from the Institut für Fangtechnik, Bundesforschungsanstalt für Fischerei, Hamburg; Dr. H. Löffler, Dr. J. Hartmann and staff of the Institut für Seenforschung und Fischereiwesen, Langenargen of the Landesanstalt für Umweltschutz Baden-Wurttemberg; and the fishery wardens from Bavaria and Baden-Württemberg.
