Nursery function of coastal lagoons: implications of habitat connectivity for the management of lagoon habitats

Abstract

Coastal lagoons and their habitats perform an important nursery function for marine migrant (MM) fish species, which enter in these ecosystems to exploit the abundant trophic resources and the best biotic and abiotic conditions. The aim of this work is to study the nursery function carried out by shallow water habitats of the Venice lagoon, i) studying the sea-lagoon connectivity, ii) studying and characterizing the habitat preferences, iii) studying the trophic ecology of a target species (Sparus aurata). In this work: i) analyzing the distribution of eggs, larvae and juveniles, collected with a bongo net and a seine net in the whole Venice lagoon, it was possible to observe that the north sub-basin is the one where MM are more concentrated, ii) developing predictive models on distribution of juveniles MM in different habitats of the north sub-basin, it was possible to observe how preferences towards environmental parameters and habitats change with ontogeny but in general saltmarshes were positively selected iii) analyzing diet, head morphology and stable isotope of S. aurata during ontogeny it was possible to observe the importance of tidal creek for the trophic ecology of this MM species. Only through the integration of these methods it is possible to evaluate the complex nursery function of the lagoons, to direct the actions of restoration and management.