Analysis of the Structure and Functioning of the Chudao Oyster Reef Ecosystem in Sanggou Bay, China

The Chudao oyster reef in Sanggou Bay, China represents a rare case of reef expansion in the context of global oyster reef degradation. However, its ecosystem structure and functioning remain poorly understood. To fill this knowledge gap, a whole-biota survey was conducted in May 2024, covering plankton, microorganisms, reef-dwelling animals, and nekton across different tidal zones. An Ecopath model was subsequently constructed to quantify trophic structure and energy flow. Results revealed a total of 30 reef-dwelling animal species, with oysters (Magallana gigas) dominant in both density (1335-1605 ind m^-2) and biomass (12.87-14.04 kg m^-2). Biodiversity indices did not differ significantly among tidal zones (p > 0.05), although relatively higher values were observed in the low-tide zone. The Ecopath model comprised 17 functional groups with trophic levels ranging from 1.00 to 3.73. Total system throughput (TST) reached 36,752.52 t km^-2 year^-1, with primary producers contributing 61% of total energy flow. Ecosystem indices indicated a relatively mature and stable ecosystem, while the overall energy transfer efficiency was low (4.21%). As the first ecosystem-level assessment of the Chudao Oyster Reef Ecosystem (CORE), this study provides valuable quantitative insights into its structural and functional characteristics and establishes a scientific basis for the conservation, management, and sustainable development of this rare expanding oyster reef ecosystem.