Association Between Estuary Characteristics and Activities of the Critically Endangered Indo-Pacific Humpback Dolphin (Sousa chinensis)

The Indo-Pacific humpback dolphin ( Sousa chinensis ) has been reported to prefer estuary habitats. This study explored the environmental factors affecting a critically endangered population off coast of Yunlin, Taiwan. We measured sighting rates and characteristics affected by watershed, including seven physical (watershed rainfall, watershed runoff, estuarine turbidity, pH, salinity, temperature, dissolved oxygen) two biological (estuarine net primary production chlorophyll concentration), at Hsinhuwei River in Dolphin activity was rate behavioral indices for feeding traveling between 2017 2018. observed that when maximum increased alongside rising temperatures spring, both foraging increased. trend maintained until heavy rainfall or river runoff occurred during late summer, which resulted high turbidity autumn winter. Turbidity significantly negatively correlated with (sighting foraging). Furthermore, we found positively concentration factors, could attract dolphins expecting more abundant prey fish supported production. provides empirical evidence on how can affect activities dolphins.