The establishment of a marine reserve in the Bay of Palma aims to encourage two distinct processes. On the one hand, it is hoped that there will be a net flow of organisms from the reserve to surrounding areas, something that would mean an increase in biomass density. On the other hand, the marine reserve will promote the maintenance of a ‘pool’ of producing organisms with a low probability of getting caught, ensuring thus the production of a sufficient number of eggs, larvae and young at an overall level, not only within the reserve but also in the surrounding area.