Abstract: Reproductive data can provide important information for the conservation and management of threatened animals. The small resident Indo-Pacific humpback dolphin (Sousa chinensis) population in Xiamen Bay is threatened by frequent exposure to anthropogenic activities, and its reproductive ecology is still unknown. Based on photo-identification data collected from August 2010 to August 2015, the present study tracked 13 reproductive females and 19 of their calves and estimated the reproductive data. Births occurred all year round but were mainly concentrated in spring and summer; the annual crude birth rate was 0.053 ± 0.025, and the annual recruitment rate was 0.028 ± 0.024; the calf survival rate to 1 year old was 0.600 ± 0.392; and females had a long inter-birth interval (4.27 ± 1.06 y). All these factors may be due to intense extrinsic anthropogenic disturbances (such as busy vessel traffic and coastal construction). In addition to these substantial extrinsic pressures, the low birth rate, low calf survival rate, and long inter-birth interval of humpback dolphins would further intrinsically preclude the sustainable survival of this population.
Key Words: Indo-Pacific humpback dolphin, Sousa chinensis, calf survival, calving seasonality, crude birth rate, inter-birth interval, photo-identification
Page Numbers: 43-52
Preliminary Study on the Reproductive Ecology of a Threatened Indo-Pacific Humpback Dolphin (Sousa chinensis) Population in Xiamen Bay, China