Objective Oyster reefs are components of coastal ecosystems that provide a number of ecological services. Although loss of oyster reefs has been documented globally, assessments of the Chinese oyster reefs status have been limited. The Yellow River Delta (YRD) is a region of particular ecological concern in China. The current investigation entailed performing a comprehensive baseline assessment of three oyster reef assemblages within the Feiyan Beach area of the YRD.

Methods A comprehensive investigation into the natural status of oyster reefs at Feiyan Beach was conducted utilizing a combination of drone mapping and scanning techniques, as well as the analysis of oyster body size traits, species identification, and sediment grain size analysis.

Results The total area of the three patch oyster reefs was estimated to be 17 772 m². The oyster abundance and biomass within the reefs were (1 957.00±574.30) ind/m² and (39.65±13.52) kg/m², respectively. The size-frequency distribution of shell height showed that the native oysters on the reefs were individuals from adult and recruited populations. The density of recruit oysters was (1232.00±318.80) ind/m². Mitochondrial cytochrome oxidase Ⅰ sequencing revealed that the oysters within the reef belong to the species Crassostrea gigas. Sediment grain size analysis revealed that the percentage of silt had the highest values, and reefs significantly facilitated the local deposition of fine-grained sediments compared to the adjacent non-reef zones.

Conclusion The results of the study demonstrate that the density and the biomass of oyster reefs in the Feiyan beach area are high, the size distribution of oysters is reasonable, and larval replenishment is not limited. Strong impact of local sediment dynamics on reef persistence suggests that sediment dynamics factors should be carefully considered before upscaling to larger restoration projects.

Significance This study constitutes the first comprehensive status survey of oyster reefs in Feiyan Beach, thereby establishing a significant foundation for the subsequent ecological restoration and conservation of oyster reefs in the YRD. Concurrently, it provides a reference research paradigm for the background investigation of oyster reefs in the entire country, with the objective of optimizing the ecological pattern and facilitating the high-quality sustainable development of coastal economic regions.