Strategic Installation of Artificial Reefs Based on Fish Ecological and Hydrodynamic Characteristics for Optimal Habitat Creation

Artificial reefs are widely deployed to enhance coastal ecosystems, yet quantifying their hydraulic behaviour and the ecological opportunities they create remains challenging. Gukdo Island, set in a rias-type archipelago on the southeastern coast of Korea, combines persistent tidal currents with high fish biodiversity, providing an ideal pilot area for testing a science-based pre-installation workflow. A regional ocean tidal model (EFDC) reconstructs multi-directional flows around the island and supplies boundary conditions to CFD simulations (FLOW-3D). Three scalar descriptors—velocity-change ratio, axis-specific vorticity, and turbulent kinetic energy—are mapped three-dimensionally and expressed as dimensionless volumes corresponding to potential feeding and refuge habitats. The results indicate that cubic block-type reef modules positioned in the modelled acceleration, deceleration, and vortex zones can create nutrient-rich upwelling sites while preserving low-energy shelters for juvenile fish, thereby maximising habitat heterogeneity. Building on these findings, a sequential screening framework is outlined: it starts with collating target-species ecological data, continues with regional hydrodynamic site selection and CFD-assisted layout optimisation, and ends with adaptive field monitoring and modular retrofit. Although demonstrated under steady tidal forcing, the workflow offers a transferable template for aligning reef design with species-specific hydraulic preferences and establishing evidence-based installation standards.