1. Department of Biology and Ecology of Fishes, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587 Berlin, Germany.
2. Division of Integrative Fisheries Management, Integrative Research Institute for the Transformation of Human–Environment Systems, and Albrecht-Daniel-Thaer Institute of Agriculture and Horticulture, Faculty of Life Sciences, Humboldt-Universität zu Berlin, Philippstrasse 13, Haus 7, 10115 Berlin, Germany.
3. Center for Limnology, University of Wisconsin-Madison, Madison, WI 53706-1492, USA.