Non-indigenous species inventory of estuarine intertidal areas; a comparison of estuaries and habitats using a hard substrate transect methodology. Pilot study within the frame of the INTERREG IV A 2 Seas project SEFINS commissioned by the NVWA. Sander Wijnhoven1, Anke Engelberts1, Angela Dekker1, et al. 1Monitor Taskforce, Royal Netherlands Institute for Sea Research (NIOZ) Final report September, 2015 Photos cover from left to lower right: a) View on the marina of Breskens with on the foreground an intertidal habitat gradient from high to low intertidal area; b) Hemigrapsus sanguineus, a non-indigenous species, as here collected at the site of Terneuzen; c) A quadrant in Ascophyllum nodosum dominated habitat, here at the site of Terneuzen, ready to be inventoried. Non-indigenous species inventory of estuarine intertidal areas; a comparison of estuaries and habitats using a hard substrate transect methodology. Pilot study within the frame of the INTERREG IV A 2 Seas project SEFINS commissioned by the NVWA. Sander Wijnhoven1, Anke Engelberts1, Angela Dekker1, et al. 1Monitor Taskforce, Royal Netherlands Institute for Sea Research (NIOZ) Final report September, 2015 Study commissioned by the Netherlands Food and Consumer Product Safety Authority (NVWA) of the Ministry of Economic Affairs (EZ) supervised by Sander Smolders (Office of Risk Assessment and Research). Study performed within the frame of the INTERREG IV A 2 Seas project ‘Safeguarding the Environment from Invasive Non-native Species’ (SEFINS), a project within the cross-border cooperation programme 2007-2013 part-financed by the European Regional Development Fund (ERDF). Study in cooperation with Morgane Barbier, Florian Rousseau & Céline Fontaine (Centre Permanent d’Initiatives pour l’Environnement (CPIE) Val d’Authie), Sharron Bosley (Wash and North Norfolk Coast European Marine Site (WNNC EMS)), Katy Owen (Norfolk County Council (NCC)), Frances Burrows (Eastern Inshore Fisheries and Conservation Authority (Eastern IFCA), Bram D’hondt, Jan Soors, Wim Jambon, Emilie Hermans, Thomas Terrie, Pieter Dhaluin, Jeroen Speybroeck, Erika Van den Bergh (Research Institute for Nature and Forest (INBO)), Arjan Gittenberger (GiMaRIS Marine Research Inventory & Strategy). NIOZ, Monitor Taskforce Publication Series 2015 – 07. Acknowledgements The authors like thank the NVWA and Sander Smolders and Johan van Valkenburg in particular for creating the opportunity to perform this pilot study, and the fruitful discussions we had on the topic. We like to thank the participants within the SEFINS project for the valuable and pleasant cooperation during fieldwork, for their contributions to the pilot study, for the discussions during meetings and for their comments on earlier versions of this report. Thanks to the ERDF co-financing the meetings and knowledge exchange within the frame of SEFINS. © Copyright, 2015. Monitor Taskforce, Royal Netherlands Institute for Sea Research (NIOZ). Yerseke, the Netherlands. All rights reserved. No part of this publication may be reproduced and/or published in print, photocopy or microfilm or on audio tape, electronically or by any other means, or saved in a storage system without prior written permission from the authors/the director of the Royal Netherlands Institute for Sea Research (NIOZ). Unless indicated differently, all used photos are taken by people involved in the project. Sander Wijnhoven, Anke Engelberts, Angela Dekker, et al., 2015. Non-indigenous species inventory of estuarine intertidal areas; a comparison of estuaries and habitats using a hard substrate transect methodology. Pilot study within the frame of the INTERREG IV A 2 Seas project SEFINS commissioned by the NVWA. Monitor Taskforce Publication Series 2015 – 07, NIOZ-Yerseke, the Netherlands. Index Acknowledgements ................................................................................................................................. 4 Abstract .................................................................................................................................................... 7 1 Introduction ..................................................................................................................................... 7 2 Material and methods ..................................................................................................................... 9 2.1 Transect monitoring ................................................................................................................. 9 2.1.1 Selection of methodology ................................................................................................ 9 2.1.2 Specifics methodology ..................................................................................................... 9 2.1.3 Implementation and deviations ...................................................................................... 12 2.2 Research sites ....................................................................................................................... 14 2.2.1 Estuaries ........................................................................................................................ 14 2.2.2 Locations and characteristics ........................................................................................ 16 2.3 Data analyses and statistics .................................................................................................. 24 3 Results .......................................................................................................................................... 25 3.1 Observed non-indigenous species ........................................................................................ 25 3.1.1. Austrominius modestus (New-Zealand barnacle) ......................................................... 25 3.1.2 Crassostrea gigas (Pacific oyster) ................................................................................. 29 3.1.3 Diadumene lineata (orange-striped green anemone).................................................... 33 3.1.4 Dreissena bugensis (quagga mussel) ........................................................................... 35 3.1.5 Dreissena polymorpha (zebra mussel) .......................................................................... 36 3.1.6 Eriocheir sinensis (Chinese mitten crab) ....................................................................... 36 3.1.7 Hemigrapsus sanguineus (Japanese shore crab) ......................................................... 40 3.1.8 Hemigrapsus takanoi (brush-clawed shore crab) .......................................................... 41 3.1.9 Incisocalliope aestuarius ............................................................................................... 42 3.1.10 Melita nitida .................................................................................................................... 43 3.2 NIS in relation to their surroundings ...................................................................................... 45 4 Discussion ..................................................................................................................................... 49 4.1 Efficiency of the methodology ................................................................................................ 49 4.2 Estuary comparison ............................................................................................................... 53 4.3 Towards the monitoring of entire systems ............................................................................. 53 4.4 Recommendations ................................................................................................................. 54 4.4.1 Recommendations to fine-tune the methodology: ......................................................... 54 4.4.2 Recommendations towards SEFINS ............................................................................. 55 5 Literature ....................................................................................................................................... 56 6 Annexes ........................................................................................................................................ 60 6.1 Annex 1. SEFINS Protocol Transect monitoring. .................................................................. 61 6.2 Annex 2. Digital field forms as provided before the start of the inventories .......................... 66 6.3 Annex 3. Overview of the inventoried lines (left and right line through different habitats) forming a transect, with a view from the high to the low intertidal zone and vice versa. .................. 68 6.4 Annex 4. Species list ............................................................................................................. 76 6.5 Annex 5. Results per Transect .............................................................................................. 83 Abstract The current report describes the methodology and application of transect monitoring as a tool to inventory non-indigenous species (NIS) on hard substrate in estuarine intertidal areas. Within the frame of the SEFINS (Safeguarding the Environment from Invasive Non-native Species) project a pilot study was executed in which the efficiency of the methodology to detect and monitor the local presence of NIS was tested. Besides, the potentials of the methodology to monitor population developments and range extension of NIS and the opportunities to link NIS