Biological and Hydrodynamic Aspects for the Design of Artificial Reef Modules for Cephalopod Molluscs in the Ares-Betanzos Estuary

Abstract

The design of an artificial reef (AR) module for improving the fishing productivity of cephalopod molluscs in the Ares-Betanzos estuary (Galicia, NW Spain) is addressed in this study. At the time of deciding on a suitable AR design, it is first necessary to assess how the different marine species use ARs so that it is possible to define the complexity of the design: its size and shape, as well as the number of nest cavities it should present and the dimensions of these cavities. Thus, two different cubic modules are proposed, both with an edge of 1500 mm. One of them can be considered as the standard design, while the other has been modified to include four open cylindrical holes. Several tools are employed to assess both proposals. Moreover, a CFD (computational fluid dynamics) model is performed. The results suggest that the flow in the interior of the tubes provides a suitable environment for cephalopod molluscs, given that circulation is produced, guaranteeing nutrient renewal. As further contributions, the present work determines how the capture of cephalopods and other species in Galician fish markets has evolved and reviews the habitat preferred by cephalopods in Galicia. It also proposes and compares two AR modules.