Abstract:

Aims: The spotted seal (Phoca largha) as a flagship species in the Yellow and Bohai Seas, plays a significant ecological indicator role. In recent years, the combined effects of climate change and human activities have posed serious threats to its habitat security. This study aims to assess the potential distribution patterns and their changing trends of the spotted seal under current and future climate scenarios, providing scientific basis for the conservation and management of this species. 

Methods: Based on 10 species distribution modeling algorithms, we selected 9 high-performing models using the AUC and TSS metrics to construct an ensemble model for predicting suitable habitats for spotted seals and quantified the contributions of key environmental factors. 

Results: The combined model performs well, with an average AUC value of 0.87 and a TSS value of 0.69, indicating high prediction accuracy. The variable analysis results show that sea surface temperature is the most critical environmental factor affecting the distribution of spotted seals, while fishing intensity and shipping traffic intensity contribute relatively less. Under the current climate conditions, the potential distribution of spotted seals mainly concentrates in the northern regions of the Bohai Sea and the Yellow Sea. Under future climate change scenarios, the suitable habitats for spotted seals will significantly shrink. In the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios, the suitable habitat area will decrease by 54.167%, 52.083%, and 65.709%, respectively; by 2100, the habitat area in the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios will decrease by 68.978%, 95.636%, and 99.772%, respectively. 

Conclusion: This study reveals the contraction trend of the potential habitat of the spotted seal under the background of climate change and its main driving factors, which can provide scientific basis for marine ecological protection in the Yellow and Bohai Seas, as well as for the management and protection strategies of the spotted seal's habitat.

Key words: Phoca largha, the Yellow Sea and Bohai Sea, species distribution models, beacon tracking, habitat suitability