Observation of Changes in Formation Locomotion in a Mother-Calf Dyad of Yangtze Finless Porpoises(Neophocaena asiaeorientalis asiaeorientalis) housed in a Captive Environment

Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) is a unique species of freshwater cetacean found in China, in the middle and lower reaches of the Yangtze River, as well as its affiliated lakes, Poyang and Dongting. It used to be known as one of the two only species of cetaceans inhabiting these waters. However, in 2006 the other species, called the Baiji dolphin (Lipotes vexillifer), went functionally extinct due to anthropogenic factors brought about by the transformation of the river into an industrial channel. These included entrapment in fishing gear, toxic pollutants, habitat fragmentation, boat collisions and prey depletion. The same causes placed the survival of Yangtze finless porpoises under threat. The population has been in constant decline since 1993 and was listed as Critically Endangered by IUCN in 2013. It has become the focus of conservation efforts of the Chinese government, scholars, and various environmental organizations. While immediate restoration of the natural habitat is not possible, much effort has been put into research on this species, including its seasonal distribution, ecology, and genetic variation. In this thesis, the adult female (F9) and her calf (F9c), who was born in the Baiji Dolphinarium of the Institute of Hydrobiology of the Chinese Academy of Sciences, were studied. Observations of changes in spatial positions during swimming and some other relevant mother-calf behaviours were conducted, and the results were compared with findings from other studies. The data revealed a wave-like pattern of progression in Echelon and Infant formations, with average values of 25.4% and 15.1% respectively. While strong fluctuations were unexpected, the mean percentage of Echelon was similar to previous studies, whereas Infant was lower than previously documented. This thesis aims to deepen our understanding of maternal care and the development of infant independence from the mother in Yangtze Finless porpoise.