Rhine Silver Eel
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VisAdvies BV Postadres Vondellaan 14 3521 GD Utrecht Nederland ABN-AMRO Rek.nr. 40.01.19.528 KvK nr. 30207643 t. 030 285 10 66 e. [email protected] w. http://www.VisAdvies.nl Rhine Silver Eel Project Title: “Population study of female downstream migrating silver eel Anguilla anguilla in the Rhine system in 2005” Project VA2005_07 30 January 2006 Author: F.T. Vriese, J.C.A. Merkx (VisAdvies) & A.W. Breukelaar (RWS-RIZA) Statuspage Titel “Population study of female downstream migrating silver eel Anguilla anguilla in the Rhine system in 2005” Compiled by VisAdvies BV Vondellaan 14 3521 GD Utrecht The Netherlands Telephone 030-285 1066 E-mail [email protected] Homepage http://www.visadvies.nl Author(s) F.T. Vriese, J.C.A. Merkx (VisAdvies) & A.W. Breukelaar (RWS- RIZA) E-mail adres [email protected] ; [email protected] ; [email protected] Number of pages 72 Keywords Transponder, Silver eel, Rhine, population study Version 2 Project number VA2005_06 Date 30 January 2006 In commission of: Rheinfischereigenossenschaft, Petrusstr. 20, 53639 Königswinter. Bibliografical reference : Vriese, F.T , J.C.A. Merkx.(VisAdvies) & A.W. Breukelaar (RWS-RIZA), 2006. Population study of female downstream migrating silver eel Anguilla anguilla in the Rhine system in 2005. VisAdvies BV, Utrecht. Project VA2005_06, 72 pages. © 2006 VisAdvies BV Niets uit dit rapport mag worden vermenigvuldigd door middel van druk, fotokopie, microfilm of op welke andere wijze ook zonder voorafgaande schriftelijke toestemming van de copyright houder(s). 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VisAdvies BV 2 Table of contents Table of contents ..........................................................................................................3 1 Rhine Silver Eel project...........................................................................................5 2 Material and methods .............................................................................................7 2.1 Telemetry (after Breukelaar et al. , 1998) ............................................................7 2.2 Mark recapture ..................................................................................................10 3 Data and data analysis .........................................................................................13 3.1 Telemetry ..........................................................................................................13 3.2 Mark recapture ..................................................................................................14 4 Results ..................................................................................................................17 4.1 Telemetry ..........................................................................................................17 4.1.1 Eel detection and migration activity................................................................17 4.1.2 Migration routes of eel in the Netherlands, escapement to sea and disappearance in the river branches ..........................................................................18 4.1.3 Swimming speed during downstream migration ............................................26 4.2 Mark recapture ..................................................................................................27 5 Discussion and conclusions..................................................................................31 5.1 Discussion .........................................................................................................31 5.2 General conclusions..........................................................................................35 6 References............................................................................................................37 7 Annexes ................................................................................................................39 7.1 Transponder implantation data of eel................................................................39 7.2 Registrations of eel on the NEDAP TRAIL system®.........................................44 7.3 Individual migration routes of eel ......................................................................48 VisAdvies BV 3 1 Rhine Silver Eel project Strategic objective: to quantify the population size and mortality of downstream migrating silver eels in the Rhine system, to trace their migration pathways. Abstract: Transponders were surgically implanted in female silver eels > 50 cm from the rivers Mosel and Sieg (180 from the Mosel, 7 from the Sieg) in late summer-autumn 2005. Migration pathways at downstream movement and mortality (transponder signal loss) were traced along the downstream sections of the river Rhine in Germany and The Netherlands. Colour pan jet batch marks were applied to female (> 50 cm) silver eels routinely caught in the Mosel. These batch marked eels were released in the Rhine in Cologne. Catches of silver eels made by an anchored stow net near Grietherbusch/Rees (DE) and commercial catches of silver eels in the most downstream sections of the Rhine (NL) were checked for these colour batch marks. A mark-recapture estimate of the total female silver eel (> 50 cm) run in 2005 is made for the Rhine. Objectives of the project: 1) Migration pathways and total mortality (TELEMETRY), a).To determine the relative importance of different migration pathways for female silver eels in the lower Rhine system in 2005. b). To quantify the total silver eel mortality in the lower Rhine in 2005 2) Total- and subpopulation size (MARK-RECAPTURE), a). To quantify the total silver eel run in the Lower Rhine in 2005. b). To quantify the silver eel run in the different branches of the lower Rhine in 2005. Participants in the project: No. Participant Acronym 1 Universität zu Köln, Zoologisches Institut, Allg. Ökologie und Uni-Köln Limnologie, 50923 Köln, Germany. Coordinator: Jost Borcherding, Aussenstelle des Zoologischen Instituts, Ökologische Forschungsstation, 46459 Rees-Grietherbusch, Germany 2 Organisatie ter Verbetering van de Binnenvisserij, afdeling Onderzoek, OVB postbus 3430, 3430 AK Nieuwegein, Netherlands . Coordinator: Jan Klein Breteler (up till August 2005) 3 VisAdvies BV, Vondellaan 14, 3521 GD Utrecht, Netherlands. VisAdvies Coordinator: Tim Vriese (from August 2005) 4 Rijksinstituut voor Integraal Zoetwaterbeheer en RIZA Afvalwaterbehandeling, Postbus 17, 8200 AA Lelystad, Netherlands. Coordinator: André Breukelaar VisAdvies BV 5 No. Participant Acronym 5 Rheinfischereigenossenschaft im Lande Nordrhein-Westfalen, RFG Römerhofweg 12, 50374 Erftstadt. Coordinator: Stefan Staas 6 Landesanstalt für Ökologie, Bodenordnung und Forsten NRW, Postfach 10 10 52, 45610 Recklinghausen, Germany. LÖBF Coordinator: Dr. Detlev Ingendahl, LÖBF NRW Kernteam Wanderfischprogramm, Heinsbergerstr. 53, 57399 Kirchhundem- Albaum 7 Struktur und Genehmigungsbehörde Nord, Rheinland-Pfalz SGN Coordinator: L. Jörgensen 8 Rheinischer Fischereiverband Nordrhein e.V., Webersbitze 20, 53804 RFV Much Coordinator: Armin Nemitz, c/o Amt für Agrarordnung Siegburg, Frankfurter Straße 86-88, 53721 Siegburg. 9 Combinatie van Beroepsvissers, Postbus 72, 2280 AB Rijswijk, CVB Netherlands. Coordinator: A. Heinen 10 Wageningen University Research Centre, Central Institute for Animal CIDC Disease Control CIDC-Lelystad, NRL on Fish and Shellfish Diseases, P.O. Box 2004, 8203 AA Lelystad, The Netherlands. Coordinator: Olga Haenen 11 Integrative Zoology, Institute of Evolutionary and Ecological Sciences IZ (IZ), Department of Biology, Van der Klaauw Laboratorium, P.O. Box 9511, 2300 RA Leiden, The Netherlands. Coordinator: Guido van den Thillart VisAdvies BV 6 2 Material and methods 2.1 Telemetry (after Breukelaar et al. , 1998) In this project the NEDAP TRAIL System® has been used. This method is based on the inductive coupling between an antenna loop and ferrite rod antenna within transponders. The identification system can be used in rivers, canals and estuaries. For the transmission mode a narrow Low Frequency (LF) band (33.25 kHz), low bit rate, approach was chosen. This combines a high sensitive receiver with a low chance of interference from radio signals and other man made disturbances. The choice of the frequency is based on the consideration that coupling between the tag, in this study a transponder, and the antenna on the river bottom is a loosely coupled transformer. This means that no radio signals are emitted and thus no interference is caused to radio users. The system consists of a detection station and implantable transponders. The network of detection stations is shown in figure 1 (situation on 1 October 2005) and the station names are given in table 1 (next page). Figure 1. Network of detection stations VisAdvies BV 7 Table 1. Names and locations of the detection stations in Rhine and Meuse Detection River (branche) or Location Start date station nr. lake 2 IJssel Kampen 01-12-96 5 Spui Zuidland 01-12-96 6 Dordtsche Kil ‘s-Gravendeel 01-12-96 7 De Noord Alblasserdam 01-12-96 8 Beneden Merwede Boven Hardinxveld 01-12-96 9 Lek Nieuwegein 01-12-96 10 Waal Vuren 01-12-96 11 Bergsche Maas Capelse Veer (Dussen) 01-12-96 12 Grensmaas Stevensweert 01-12-96 13 Rijn Xanten (BRD) 22-05-97 14 Oude Maas Spijkenisse 03-11-97 15