Identifying priority habitat for future spatial conservation and management decisions of East Asian finless porpoise within Miaodao Archipelago waters, China

Abstract

In the realm of marine biodiversity conservation, understanding the dynamics between species' spatial distributions, habitat utilization, and human impacts is crucial. This knowledge is indispensable for marine spatial planning, facilitating the identification and mitigation of conflicts between human activities and the conservation goals of marine ecosystems. The East Asian finless porpoise (Neophocaena asiaeorientalis sunameri), classified as endangered by the IUCN Red List, is the only cetacean routinely observed in the vicinity of the Miaodao Archipelago. To identify key areas for this species and assess the impact of human activities, boat-based surveys were conducted from 2019 to 2023, covering 6220 km² of the Miaodao Archipelago's waters. These surveys recorded 1610 porpoise sightings over 75 survey days. Spatial analysis revealed that the East Asian finless porpoises primarily frequent three core density areas characterized by high sighting densities. Additionally, intermediate density and habitat range areas were delineated, which are essential for the porpoises' movement between these core regions. The study also analyzed the spatial usage of porpoises within and outside areas affected by human activities, revealing that sighting densities were significantly higher in regions with minimal human impact (p < 0.01). Based on these findings, it is proposed that the areas with high porpoise sighting densities be managed as a unified protected area network. These findings should guide future conservation and management strategies within the National Park to ensure the effective preservation of this endangered species.