In this paper a numerical method for tag shedding calculation from double tagging data was used to estimate the tag loss rate in Palinurus elephas from capture-mark-recapture experiments. Four consecutive experimental surveys during years 1999-2002 inside the Columbretes islands marine reserve (CIMR) were carried out and the captured spiny lobsters were dorso-laterally double-tagged with T-bar anchor tags on both sides between the first and second abdominal segments. The recaptures during the following years (2000-2008) were recorded and the evolution of the proportion of single- and double-tagged specimens was analysed. The immediate tag loss produced after tagging could not be accurately modelled, but in view of the results is believed to be low. The probability of tag loss per year was estimated in 6% (sexes combined). The factors causing this tag loss and the repercussion of this rates of shedding on further studies are examine
