Author(s): Shuai Yuan; Xueqin Liu; Wenqi Shi; Guanfei Lai; Ning Xu; Yuxian Ma; Shujuan Lai
Linked Author(s):
Keywords: Sea ice environment; Spotted seal (Phoca largha); Sea ice indicators; Breeding and pup-rearing; Habitat suitability analysis
Abstract: Climate change poses the most serious challenge to global biodiversity. The spotted seal (Phoca largha) is the sole flagship ice-breeding marine mammal of the Yellow and Bohai Sea ecoregion and the only pinniped that reproduces in Chinese waters, with sea ice constituting the primary habitat requirement during the breeding season. Since the early 20th century, the wild spotted seal population in China has declined sharply from over 7,000 individuals in the early 1930s to approximately 1,000 today. The icebound waters of Liaodong Bay in the Bohai Sea represent the southernmost of eight global spotted seal breeding areas, where ice extent, offshore distance, thickness, and duration critically govern breeding and pup-rearing success. This study presents the first systematic analysis of sea ice condition indicators affecting spotted seal breeding habitat suitability and evaluates annual changes in suitable breeding areas over twelve consecutive winters (2010/2011–2021/2022). Three indicators are defined: number of days with maximum ice thickness ≥ 15 cm, maximum offshore distance of drift ice, and mean drift ice distribution area. Results show that five winters were Suitable, two Sub-suitable, and five Low-suitable for spotted seal breeding. The findings provide a scientific basis for enhancing spotted seal population resilience to climate change and for regional marine ecosystem conservation and management.
Year: 2026