Zoological Studies

Vol. 50 No. 6, 2011

Range Patterns of Resident Indo-Pacific Humpback Dolphins (Sousa chinensis, Osbeck 1765) in Xiamen, China: Implications for Conservation and Management

Bing-Yao Chen1, Dong-Mei Zheng2, Jian-Feng Ju1, Xin-Rong Xu1, Kai-Ya Zhou1, and Guang Yang1,*

1Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal Univ., Nanjing 210097, China
2College of Oceanography and Environmental Science, Xiamen Univ., Xiamen 361005, China

Bing-Yao Chen, Dong-Mei Zheng, Jian-Feng Ju, Xin-Rong Xu, Kai-Ya Zhou, and Guang Yang (2011) Because Xiamen, China’s Sousa chinensis population is under heavy anthropogenic pressure, there is an urgent need for effective management and protection especially at key sites which are associated with vessel traffic. In the present paper, the home range sizes of 21 resident dolphins in Xiamen were estimated, and interactions of their range sizes with features such as social clusters, paired or unpaired, coefficients of association (COAs) were assessed. In addition, various interactions of age class and sex were also explored. As a result, the mean range sizes based on the minimum convex polygon (MCP), 95% kernel, and 50% kernel, and the linear distance were respectively 84.06 km2 , 162.48 km2 , 29.7 km2 , and 20.74 km. Individuals’ home ranges were concentrated around the Jiulong River Estuary and Tongan Bay, corresponding well with 2 social clusters. Range sizes of the 2 social clusters did not significantly differ. Paired dolphins (preferred partners) had significantly smaller ranges than unpaired ones. At the multiple-partner level, dolphins with more partners had significantly larger ranges than those with fewer partners. Animals with high COAs had significantly smaller MCP range sizes and linear distances than those with low COAs. In general, there were no significant changes of home ranges of individuals in different age classes of the population. The range sizes of 8 females were slightly (non-significantly) larger than those of other dolphins of unknown sex. According to our results, the Jiulong River Estuary and Tongan Bay are identified as core areas should be given priority consideration. Further understanding of the overall range pattern of this population requires cooperation with scientists who work in neighboring waters of Kinmen I. as well as other nearby populations along the Chinese coast.

Key words: Association, Kernel, MCP, Range, Resident.

*Correspondence: Tel: 86-025-85891163. Fax: 86-025-85891163. E-mail:gyang@njnu.edu.cn