Dr. Ulrich Schwevers is director of the Institute of Applied Ecology (Institut für angewandte Ökologie) in Germany. His interdisciplinary knowledge, notably on river ecology and hydraulic engineering, has enabled him to coauthor several publications with guidelines on fish ways for upstream and downstream migrants. He has travelled extensively in the course of his work and participated in over 300 projects, e.g. in Germany, Switzerland, France and the Netherlands.   Dr. Beate Adam, a freelance fisheries biologist specializing in fish behavior, has more than 20 years of experience observing and researching fish and other aquatic biota under field and laboratory conditions. Educated at several German Universities she has been for more than two decades chairperson of interdisciplinary committees that produced manuals on ecological water engineering. She is author or co-author of more than 200 books, scientific papers, popular articles and reports on freshwater fish.