Textural Characteristics might Influence Donax trunculus Shellfishing Banks Exploitability

Resumo

In this study we combine textural and compositional information to characterize the intertidal sediments from three relevant shellfishing banks located in the Rías Altas (Vilarrube, Lombo das Navallas) and Rías Baixas (Playa America) of Galicia (NW Spain). The purpose of this study is to explore the relevance of the sediment characteristics as a key parameter in the decline of commercially exploitable populations of the bivalve Donax trunculus in two of the banks (Lombo das Navallas and Playa América) but not in the other (Vilarrube). The sediments of the three areas show their own distinctive sedimentary characteristics that became defined by their grain size parameters, mineralogical and elemental composition. This is the result of regional land supplies from the erosion of drainage areas and sea cliffs together with the contribution of modern carbonate bioclasts. Notably, the sediments of Vilarrube are characterized by moderately sorted to well sorted fine sand showing little spatial variability. According to our results, sediment texture seems to be a relevant parameter for the settlement and growth of commercial populations of Donax trunculus