The Lake Constance annual catch statistics for both professional and recreational fishery provide important information on the development of fish stock. It should be noted, however, that neither the fishing effort nor the adjustments of the equipment are taken into account. A reduction in mesh size certainly has an influence on the catch result but does not apparent in the following graphic.
Catch statistics of the professional fishery in Upper Lake Constance for the years 1910 – 2016
Situation of nutrients of Upper Lake Constance (source: IGKB)