Shipwrecks can mirror predator assemblages of pelagicpinnacles but may lack the trophic balance of natural reefenvironments.

Abstract

Artificial reefs are widely deployed to enhance fish populations, yet their capacity to replicate the ecological roles of natural reef systems remains uncertain, and comparisons are often limited to nearby fringing reefs. Such assessments may overlook how structural features influence ecological outcomes. This study compared fish assemblages across shipwrecks, pelagic pinnacles, and fringing reefs in the Gulf of Thailand to evaluate how artificial structures align with natural patterns of community structure and trophic composition. Natural reef sites were selected to represent contrasting structural profiles, with pinnacles characterized by high vertical relief and fringing reefs by lower-relief slopes. This design enabled assessment of whether high-relief artificial structures, such as shipwrecks, more closely reflect fish communities found on similarly structured natural reefs. Bayesian multivariate models applied to 350 underwater surveys from 14 sites showed that shipwrecks resembled pelagic pinnacles in supporting mesopredators and higher trophic level predators, but had consistently lower representation of grazers and invertivores relative to both natural reef types. These results indicate functional divergence likely driven by reduced benthic complexity and limited forage availability. While shipwrecks may support fisheries species and predator biomass, they do not fully function as ecological analogues of natural reefs. Findings highlight the importance of aligning artificial reef design with defined ecological objectives and considering structural context in management strategies across tropical reef systems worldwide.