Vol.:(0123456789) 1 3 Mar Biol (2017) 164:79 DOI 10.1007/s00227-017-3114-0 ORIGINAL PAPER Attachment capacity of the sea urchin Paracentrotus lividus in a range of seawater velocities in relation to test morphology and tube foot mechanical properties Mishal Cohen‑Rengifo 1,2  · Claire Moureaux 2  · Philippe Dubois 2  · Patrick Flammang 1   Received: 19 October 2016 / Accepted: 17 February 2017 © Springer-Verlag Berlin Heidelberg 2017 calculated a safety factor to predict the fow velocity that would cause detachment from the substratum. It showed individuals from the most exposed habitat would resist higher fow velocities (up to 7.59 ± 0.90 m s −1 ). Both mor- phometry and tube foot mechanical properties vary among subpopulations and show an intraspecifc plasticity in P. lividus. Although, diferences in sea water velocity may be one cause of this intraspecifc variation, it likely results from a combination of biotic and abiotic factors. Abbreviations σ Stress Δl Extension ε Strain µ Dynamic viscosity ρ Density ADV Acoustic Doppler velocimeter ANOVA Analysis of variance CC Cap de la Chèvre C d Drag coefcient C l Lift coefcient F d Disk detachment force F g Global detachment force F hydro Hydrodynamic force F max Maximal attachment force F t Traction force FWL Fractional weight loss IL Illien I Length l o Initial length L Sea urchin length (test diameter with spines) MO Morgat PS Polystyrene PVC Polyvinyl chloride Re Reynolds number Abstract Intertidal rocky shores are stressful environ- ments where benthic invertebrates experience large wave- induced hydrodynamic forces that can detach them from the substratum. The tube feet of echinoids counteract these forces and help them remain securely afxed. Sea urchins display a high degree of phenotypic plasticity which may help them cope with hydrodynamic stress. We evaluated whether habitats presenting diferent seawater velocities induce plastic responses in the attachment capacity of the sea urchin Paracentrotus lividus by quantifying their mor- phology and the adhesive and mechanical properties of their tube feet. Intertidal adult sea urchins from three sub- populations were collected around the Crozon peninsula (France). Localities difered according to measured water velocities. Size was signifcantly lower in the two most exposed sites where sea urchins also presented a higher density of tube feet. Tube foot adhesive properties were not signifcantly diferent between sites, but their extensi- bility and toughness were signifcantly higher in individu- als from the most exposed site. Using this information, we Responsible Editor: M. Byrne. Reviewed by undisclosed experts. * Mishal Cohen-Rengifo mishal.cohen@student.umons.ac.be Patrick Flammang patrick.fammang@umons.ac.be 1 Laboratoire de Biologie des Organismes Marins et Biomimétisme, Institut des Biosciences, Université de Mons, 23 Place du Parc, 7000 Mons, Belgium 2 Laboratoire de Biologie Marine, (CP160/15), Université Libre de Bruxelles, 50 Av. F.D. Roosevelt, 1050 Brussels, Belgium