Evaluating Adhesive Materials for Effective Outplanting of <i>Acropora</i> Corals: A Comparative Analysis of Adhesion Performance, Biocompatibility and Cost‐Effectiveness

ABSTRACT Coral restoration is a critical but costly endeavour, and the selection of appropriate outplanting materials plays a key role in both the effectiveness and cost‐efficiency of these projects. This study aims to evaluate and compare the suitability of seven adhesive materials for coral outplanting, focusing on their adhesion performance, operability, biocompatibility and cost‐effectiveness. The study emphasises the importance of selecting adhesives with optimal curing time and tensile strength to ensure successful coral fixation, with Portland cement, the mixture of Portland cement and quick‐setting cement, and epoxy putty adhesive emerging as the most effective materials in this regard. Subsequently, the three materials were tested for more than half a month for underwater coral outplanting. The results indicate that adhesives, particularly epoxy putty adhesive and Portland cement, are viable and cost‐effective alternatives to traditional outplanting nails, offering superior underwater operability and stability. Portland cement is highlighted for its affordability and ease of use, making it increasingly favoured in large‐scale restoration efforts. However, the potential biocompatibility issues associated with Portland cement‐based adhesives necessitate further investigation. These findings suggest that adhesives can serve as an efficient and cost‐effective technique for underwater coral fixation during coral restoration, although careful consideration of environmental factors and additional field testing are essential to validate their effectiveness across varied conditions.