Evaluating management effectiveness of marine protected areas in regulating fishing pressure on spotted seal (Phoca largha) habitats

Marine protected areas (MPAs) have become effective tools for biodiversity conservation and fishery management. They provide a safe environment for the breeding and development of fish populations and endangered species. Spotted seals ( Phoca largha ) are listed as first-class national protected species in China due to habitat loss and threats from human activities. Spotted seals inhabiting the Bohai and Yellow Seas represent a small population with independent genes and hold substantial ecological conservation value. Although designated MPAs have been established to mitigate disturbances caused by human activities, research on their effectiveness remains limited. This study assessed the management effectiveness of two reserves in the Bohai Sea and its adjacent sea areas of China on spotted seal habitats in terms of fishing activities. The two reserves are the Dalian Spotted Seal National Nature Reserve and the Miaodao Archipelago Seal Provincial Nature Reserve. The assessment indicator of fishing activities was developed based on Automatic Identification System (AIS) data of fishing vessels in 2018 and 2021. The spatio-temporal differences of fishing activities within and around the reserves were examined. The damage risk to fishery food resources within the reserves caused by fishing activities was evaluated using the risk source-acceptor-response framework. The results indicated that fishing activities within the spotted seal reserves were effectively regulated. However, fishing activities in the surrounding waters remained high. The protective effect in the Miaodao Archipelago Seal Nature Reserve was relatively weak, with fishing effort 2.90 times higher than that in the Dalian Spotted Seal Nature Reserve. Over 99% of the sea areas within the reserves were at moderate or above damage risk to fishery resources. To address these issues, we propose delineating clear core protected zones, enhancing the protection level of the Miaodao Archipelago Seal Nature Reserve, moderately expanding MPA boundaries, and strengthening the regulation and monitoring of fishing activities within the spotted seal reserves. These findings can provide a theoretical basis for optimizing management strategies in spotted seal reserves and offer valuable insights for ecological conservation and policy guidance.