Look at these videos from IFREMER (a French institute for sea observation)
Crab : http://haxo.vendee.e-lyco.fr/activites-periscolaires-options-et-voyages/projets-europeens/crustaceans-are-mooving-look-at-the-crab-24159.htm
Spiny lobsters : http://haxo.vendee.e-lyco.fr/activites-periscolaires-options-et-voyages/projets-europeens/crustaceans-are-mooving-the-spiny-lobsters-24160.htm