1. Kelp Marine Research , Hoorn 1624 CJ, The Netherlands
2. Department of Coastal Systems, Royal Netherlands Institute for Sea Research, PO Box 59 , Den Burg 1790 AB, The Netherlands
3. Cerema-University Gustave Eiffel, UMRAE, Acoustics Group of the Laboratory of Strasbourg , Strasbourg F-67210, France
4. Département de Biologie, ENS École Normale Supérieure de Lyon , Lyon Cedex 07 69342, France
5. Azorean Biodiversity Group & Center for Ecology, Evolution and Environmental Changes & CHANGE—Global Change and Sustainability Institute, University of the Azores, 9700-042 Angra do Heroísmo, Terceira , Azores, Portugal