Conectividade ecológica no Oceano Atlântico Tropical por meio de modelagem numérica

Abstract

The understanding of the recruitment and conectivity of marine species that has planktonic stages is a complex task and it needs a multidisciplinary approach. For example, the lobsters are an important fishery resource for the Northeast region of Brazil that has been exploited for many years. These organisms have a very complex life cicle, with the duration of a pelagic larval stage of one year with up to 11 larval stages and a puerulus stage, in which it acquire the ability to swim and migrate from the ocean to coastal habitats. For showing such a long pelagic larval duration, this larvae can be transported to places far from where the spawn has occured. Since the adult individuous are benthic and cannot survive to depths higher than 200 m, one of the questions to be answered is the origin of the lobster stocks found in São Pedro e São Paulo Archipelago (ASPSP), in the Fernando de Noronha Archipelago (FN) and in the Rocas Atoll (AR). Surface circulation data, between 2002 and 2012, from the reanalysis of the HYCOM/NCODA global model, with resolution of 0.08°, were incorporated to the Ichthyop, a, Individuous Based Model, to study the lobster larvae dispersion. The model domain covers the whole intertropical Atlantic region between the latitudes of 30° N and 25° S, where the three target islands are in. The simulations were realized in backward mode with the initial release of larvae, treated as passive particles, where the islands are situated and monitored for 7 months starting from April and September. ASPSP, FN, AR and the brazilian continental shelf (PCB) express a conexion where one region can be used as a ecological trampolines and guarantee the indirect genetic flux within the regions. Spawns in the PCB in February ensure a larger conectivity. The Ascension Island (IA) and Cape Verde (CV) can also be a source of larvae to the islands, although in a much lower grade. In this case, the larger conectivity is given by the September, to IA, and April, to CV, spawns. Even though the African coast shows highest percentages of virtual particles in conexion, it cannot be expected that this region feeds the brazilian islands with lobsters, for there are no equivalent populations in Africa. There is a large interannual variability in the conectivity between these regions. The results here found can also be useful in dispersion and surface advection of materials in general and conectivity studies to other species with a planktonic stage in its life cicle.