Will we see you again? Population evaluation of Palinurus elephas inside a marine reserve from Capture-Mark-Recapture data

Abstract

To achieve an effective management of the marine exploited populations it is necessary to understand their dynamics and the processes driving short- and long-term changes. Key population parameters such as survival and movement can be estimated by means of capture-mark-recapture studies, based on the capture, tagging and re-encounter of the individuals at later times. The Cormack-Jolly-Seber model, which assesses the apparent survival i and the recapture rate pi of a population conditional on first capture, was applied to European spiny lobster Palinurus elephas data from the Columbretes islands marine reserve to evaluate the evolution of this population after closure to fishing over. Particularly strong winter conditions were reported for some years during the period of study whcih were reflected as an increase in the estimate of the encounter probability and a decrease in their survival rate. P. elephas showed a relatively high plasticity against short-term environmental effects, with the apparent survival quickly returning to pre-storm levels. Also a slight increase in survival was identified for this protected population over time. These preliminary results are discussed in terms of the factors affecting the dynamics of this population and the implications for the management of this exploited stock