This study examines how Atlantic cod use four artificial reefs in an offshore wind farm (OWF). Using acoustic telemetry, researchers tracked cod behavior and movement around the reefs with fine temporal and spatial resolution. The study found that the reefs were particularly attractive to cod, who remained near them for long periods, often hiding within the structure. Although two reefs had additional scour protection, this did not noticeably affect cod behavior. If hard substrate is important for Atlantic cod population growth in the Southern North Sea, these concrete pipe reefs could help expand this habitat, complementing the limited space offered by OWF structures.

• Six (of the sixteen) acoustic receivers were lost during the project. This did not affect the analysis or results of the study, but it counted as a large part of the total receivers and a substantial financial loss.
• Since equipment cannot be moored in the OWF, each acoustic receiver was placed on the seabed without surface markers. Frames were recovered using acoustic releases embedded in each unit.
• Losses were likely due to depleted receiver batteries or barnacle buildup, which interfered with the release of recovery buoys.
• Equipment was serviced every 9-12 months, but future studies should aim for more frequent servicing, such as every 6 months.
• Tagging the animals was challenging because it required optimal weather and low current conditions.
• Balancing the need for optimal conditions with a stringent vessel schedule was successful, but also challenging.