This research involved quarterly sampling across a one-year period at three mudflat aquaculture regions under three different management styles, to evaluate the influence of aquaculture cycles on sediment composition and macrofaunal functional diversity. Moreover, the study explored the potential of macrofaunal functional diversity as a biological indicator for assessing heavy metal contamination. Our results revealed that aquaculture cycles and management styles exerted significant influence on the concentrations of heavy metals in the sediment. Specifically, lower levels of contamination were recorded during the spring and autumn harvest periods, while higher concentrations were observed during the summer growth phase. The implementation of strict aquaculture management practices has proved effective in reducing sediment contamination. Hg and Cr were identified as the primary contributors to heavy metal accumulation in the aquaculture regions. Functional diversity indices were not significantly correlated with heavy metal indices. However, fuzzy correspondence analysis (FCA) revealed a distinct shift in community composition. As contamination levels increased, sensitive filter-feeding species were progressively replaced by opportunistic polychaetes. Conversely, the AMBI and M-AMBI indices were significantly correlated with heavy metal concentrations, highlighting their efficacy as reliable indicators of sediment contamination. The research further identified multiple pollution sources, with industrial effluents and aquaculture activities being the most prominent. These findings provide a scientific foundation for the development of ecological management strategies and for the assessment of heavy metal contamination in mudflat aquaculture systems.

macrofauna, functional diversity, heavy metals, temporal variation, mudflat aquaculture