Editorial and subsequent fish pass construction on nase in the Iller, a Bavarian tributary of the Danube. Georg Janauer concen- Gertrud Haidvogl: Editor DanubeNews, Institute of Hydrobiology and trates on the spread of invasive plants in the Danube and Aquatic Ecosystem Management, University of Natural Resources and Life Sciences Vienna (BOKU), Austria, e-mail: [email protected] possible management measures to control or restrict them. Bernd Cyffka: Editor DanubeNews, Applied Physical Geography, Michael Neumayer and his colleagues describe their con- Catholic University of Eichstätt-Ingolstadt and Aueninstitut Neuburg/Donau, ceptual approach and models for evaluating the effec­ Germany, e-mail: [email protected] tiveness of natural and decentralised flood protection Dear readers, ­measures for streams in Bavaria. Finally, Johanna Weiden- dorfer analysed in her bachelor thesis the application of When we started planning this issue of Danube News in several macrophyte-based assessment methods for Serbian January 2020, we assumed that it would be prepared as Danube backwaters. “business as usual”. As you all know, our world was turned upside down in February or at the latest in March 2020. In As some of you may have read or been informed, the 43rd order to prevent the spread of the SARS-CoV-2 virus, we all IAS conference will also have to be postponed. We hope to had to move to home workplaces, adapt to various restric- meet you at the currently scheduled date of 26–29 October tions of daily life and at the same time still take over the 2020 at the Aueninstitut Neuburg. Please check for news at daily work tasks and often the care of children at home or iad2020.ku.de. of elderly relatives. We would like to thank all authors, our always supportive Under these circumstances, we are especially pleased that graphic designer and the printing shop for their efforts and Danube News 41 will be published in time and in the same contributions during this challenging time and wish all our quality as you are used to. In this issue, Tobias Epple and his readers health and strength for the time ahead. colleagues provide insights into the effects of fragmentation

The life cycle of nase (Chondrostoma nasus) before and after the construction of hydropower plants in the river Iller (Bavaria, Germany) and its migration behavior through fish-bypass channels

Tobias Epple: Institute of Geography, University of Augsburg, Germany, has been studied daily with fish counting pools over 3 years e-mail: [email protected] and correlated with abiotic factors. The main abiotic factors Arne Friedmann: Institute of Geography, University of Augsburg, Germany, e-mail: [email protected] that influence the migration patterns of juvenile and adult Karl-Friedrich Wetzel: Institute of Geography, University of Augsburg, nase are water temperature and day-length. The highest Germany, e-mail: [email protected] numbers of migrating adult nase have been documented at Oliver Born: Fischereifachberatung des Bezirks Schwaben, water temperatures between 9.0 and 9.9° C and increasing e-mail: [email protected] day-lengths between 13:00 and 13:30 hours. Through a literature study, electrofishing and the fish counting pool, Abstract the life cycle of the nase has been investigated at the hydro­ The middle section of the river Iller (Bavaria, Germany) power plant Illerstufe 6. Prior to the fragmentation, nase from is fragmented by weirs since the mid-20th century. At five the whole river Iller and probably even from the river Danube hydropower plants (Illerstufe 4 – 8), fish-bypass channels have migrated to two spawning habitats in the upper river have been constructed between the years 2013 and 2016. Iller. After the fragmentation, migration has been impossible The upstream migration of the European fish species nase over a long time and there has been a large reduction of (Chondrostoma nasus) through the fish bypass channels the nase population in the middle section of the river Iller.

Danube News - June 2020 - No. 41 - Volume 22, https://www.danube-iad.eu Page 1 ISSN 2070-1292

Bulletin of the International Association for Danube Research (IAD) Informationsblatt der Internationalen Arbeitsgemeinschaft Donauforschung (IAD)

International Association for Danube Research (IAD)

Presidium President Vice President General Secretary Dr. Cristina Sandu Prof. Dr. Thomas Hein PD Dr. Katrin Teubner

DE CH AT CZ SK HU HR Prof. Dr. Bernd Dr. Edith Dr. Gertrud Dr. Petr Prof. Dr. Prof. Dr. Vera Dr. Melita Member Country CYFFKA DURISCH-KAISER HAIDVOGL PARIL Vladimír KOVÁCˇ ISTVÁNOVICS MIHALJEVIC Representatives SI BA RS RO BG MD UA N.N. N.N. Dr. Snezana Dr. Grigore Dr. Roumen Prof. Dr. Ion Dr. Artem RADULOVIC BABOIANU KALCHEV TODERAS LYASHENKO

Water Quality Biotic processes Microbiology Phytoplankton / Macrophytes Floodplain ecology Prof. Dr. Carmen Prof. Dr. Thomas Prof. Dr. Alexander Phytobenthos Prof. Dr. Georg Prof. Dr. Bernd POSTOLACHE HEIN KIRSCHNER PD Dr. Katrin TEUBNER JANAUER CYFFKA Expert Groups LTSER and Fish Biology / Invasive Sustainable Development Ecotoxicology Delta / Fore-Delta Environmental History Fishery Alien Species & Public Participation N.N. Dr. Julian Dr. Gertrud Haidvogl Dr. Mirjana Dr. Teodora Dr. Harald KUTZENBERGER NICHERSU Prof. Dr. Martin Schmid LENHARDT TRICHKOVA Prof. Dr. Doru BANˇ ADUCˇ

CH MD

LIUBLIANA

Hydrological catchment of the River Danube RMN

General Secretary: Editors: Layout: International Association for Danube Research (IAD) (Internationale Arbeitsgemeinschaft Donauforschung) Prof. Dr. Bernd Cyffka Diener-Grafics GmbH, 8006 Zürich PD Dr. Katrin Teubner CU Eichstätt-Ingolstadt [email protected] Dept. of Limnology & Bio-Oceanography [email protected] Printing: Faculty of Life Sciences, University of Vienna Dr. Gertrud Haidvogl Althanstrasse 14, A – 1090 Vienna BOKU Vienna Satz & Druck Edler [email protected] [email protected] Am Kreuzweg 5, D-86668 Karlshuld

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