Urbanization Compromises the Sustainability of Coastal Ecosystems: Insights from the Reproductive Traits of the Bioindicator Clam Donax trunculus

The sustainability of coastal ecosystems, associated fisheries, and environmental quality is increasingly threatened by anthropogenic activities and rapidly expanding urbanization. This study investigated the ecological impacts of increased coastal urbanization on intertidal sediment quality and the biological parameters of the wedge clam Donax trunculus along the central Moroccan Atlantic coast. Between 2018 and 2022, a period characterized by intensified urban activity, total organic matter (TOM) in sediment significantly increased, whereas temperature and pH remained stable. Concurrently, D. trunculus populations experienced notable declines in abundance and biomass, along with marked disruptions in reproductive dynamics. The proportion of sexually mature individuals decreased, while spent individuals and male-biased sex ratios became more prominent. These findings suggest that urbanization-related pressures such as sediment enrichment, pollution, and physical disturbance are exerting measurable stress on this key bioindicator species. The results highlight the need for improved coastal management to mitigate the ecological consequences of rapid urban expansion on coastal sustainability.