Bycatch is the dominant threat affecting Indo-Pacific Bottlenose Dolphins throughout their range. However, there are very few estimates of mortality rates or abundance over time to evaluate the severity of the impact. In Australia, the major threats include bycatch in trawls and gillnets as well as in shark nets set at popular coastal beaches to protect bathers (Hale 1997, Paterson, 1990).
Indo-Pacific Bottlenose Dolphins are among the cetacean species most commonly kept in captivity in Asia (Wang et al. 1999, Reeves et al. 2003). Since the early 1960s, live-captures of T. aduncus for oceanarium display have occurred in many areas, including South Africa, Australia, Taiwan, Japan and Java (Best and Ross 1984, Tas’an and Leatherwood 1984, Reeves et al. 1994, Cawthorn and Gaskin 1984, Kasuya et al. 1984). Several diseases appear to be increasing in occurrence in coastal small cetaceans, raising concern for the health of these animals. Since the early 2000s, there have been several dolphin mortality events in Australia that have included T. aduncus (Kemper et al. 2016). In these events all the dolphins tested positive for the cetacean morbillivirus. Climate change, especially increases in sea surface temperature that are prevalent throughout coastal areas of the Indian Ocean, are negatively affecting coastal habitats such as coral reefs and seagrass beds used by Indo-Pacific Bottlenose Dolphins.