  The primary aim of ANTARES is neutrino astronomy with upward going muons
created in charged current muon neutrino interactions in the detector and its
surroundings. Downward going muons are background for neutrino searches. These
muons are the decay products of cosmic-ray collisions in the Earth's atmosphere
far above the detector. This paper presents a method to identify and count
electromagnetic showers induced along atmospheric muon tracks with the ANTARES
detector. The method is applied to both cosmic muon data and simulations and
its applicability to the reconstruction of muon event energies is demonstrated.
