Comunitats pelàgiques i estudis sobre processos de exportació i retenció larvària a l’entorn del Parc Nacional Marítim-Terrestre del arxipèlag de Cabrera (PNMTAC)

The creation and delimitation of marine protected areas has generally been carried out without considering the three-dimensional and open nature of the marine environament, neither planktonic dispersion or the hydrodynamics, which determine the composition, structure, distribution and dynamics of the communities. The Maritime-Land National Park of the Cabrera Archipelago (MLNPCA) was not an exception.Nowadays, accurate information on its hydrographic environment, pelagic communities, and even on the processes of export and larval retention inside the MLNPCA, is crucial for the correct management. This chapter describes the current state of knowledge of the pelagic communities in the MLNPCA environment, previously explaining the sampling strategies of the main programs and research projects carried out in the last 25 years. The main results and conclusions of the studies on the communities that inhabit the water column, from bacteria to large pelagic fish, are summarized, paying special attention to the processes that affect the spatio-temporal dynamics of meroplankton (eggs and larvae of marine organisms). It is worth highlighting the great biodiversity observed in many taxonomic groups, similar to subtropical areas. An annual cycle is given in the composition of the different communities, with two well diferentiated periods: one of a mixture water column, more productive, and another with a strong stratification (thermocline) that limits the vertical moviments. However, there is a great variability in the pelagic communities, associated with surface water bodies, wether those of Atlantic origin or Mediterranean residents. As regards the processes of export and larval retention in the MLNPCA, they depend mostly on a combination of ephemeral retention processes (dependent on the wind and topography), and on the initial distribution and evolution of the behavior of larvae along the ontogeny. The fish populations of MLNPCA are mantained self-sufficiently because of self-recruitment.