The decline in biodiversity is one of the most pressing ecological challenges facing our planet. Given the uneven distribution of biodiversity and the limitation of conservation resources, it is crucial to maximize conservation benefits within our current capabilities. Focusing efforts on the priority protection of some important biodiversity areas is a practical and efficient approach at present. Among them, the Key Biodiversity Areas (KBAs) is an effective method. However, the high mobility and connectivity inherent in marine ecosystems pose significant challenges when it comes to defining the boundaries of critical areas for biodiversity conservation. In this study, we identified marine eco-regions of key biodiversity for priority conservation in China’s coastal waters adopting the methodology of Key Biodiversity Areas (KBAs).Taking into account the distinctive features of China's marine ecosystems and biodiversity, as well as the availability of data, criteria for identifying Marine Key Biodiversity Areas (MKBAs) have been established focusing on three key criteria:  threatened species, geographically restricted ecosystem types and biological processes.
By integrating comprehensive marine biodiversity distribution data. In the assessment of threatened species, the study included species such as the Indo-Pacific humpback dolphin, Bryde's whale, the spotted seal, sea turtles, various fish, and coastal migratory birds. Geographically restricted ecosystem types encompass mangroves, coral reefs, seagrass beds, and salt marshes. Additionally, biological processes of biodiversity such as key marine breeding and spawning grounds for species like sea turtles and spotted seals, are also considered. A total of 34 key marine biodiversity areas have been identified in this study, predominantly located in the Minjiang Estuary of Fujian, the Leizhou Peninsula in Guangdong, the Pearl River Estuary, and the waters surrounding Hainan Island. These regions are of paramount importance for the conservation of endangered species, including chordates and coastal wetland birds, as well as for the preservation of typical ecosystems such as mangroves and coral reefs. This research offers vital insights for spatial planning and the management of marine biodiversity conservation efforts in China, and it also aids in the pursuit of global biodiversity conservation goals.
 

key biodiversity areas, biodiversity conservation, coastal ecosystems, conservation prioritization, marine biodiversity management