Whale temples are unique repositories for understanding marine mammal diversity in Central Vietnam

In recent decades, several studies and reviews have contributed new data on marine mammal composition and distribution in Vietnam, including surveys of whale temples along the coast in the southern part of the country. Whale temples have amassed a sizeable number of specimens that have been used as a valuable source of information concerning marine mammals in Vietnam. Previous studies have examined some whale temples in southern Vietnam, but contents of whale temples along the whole coast of Vietnam have not been fully documented. Here we surveyed 18 whale temples in the central part of Vietnam in Đà Nẵng, Quang Nam, Quang Ngai, and Thừa Thiên-Huế Provinces, an area that had not been scientifically documented previously. We identified and measured 140 individual marine mammals from 15 species, four families, and two orders (Artiodactyla, Sirenia). By far the most numerous species encountered (n=41) was the inshore Indo-Pacific finless porpoise (Neophocaena phocaenoides). We also encountered >10 skulls of two other taxa: bottlenose dolphins (Tursiops sp.) and the IndoPacific humpback dolphin (Sousa chinensis). Other delphinid species included Stenella longirostris, S. attenuata, Globicephala macrorhynchus, Grampus griseus, Feresa attenuata, Pseudorca crassidens, Lagenodelphis hosei, and Delphinus delphis tropicalis. We identified one specimen of humpback whale (Megaptera novaeangliae) and three of Omura’s whale (Balaenoptera omurai), increasing the number of records of the recently described Omura’s whale in Vietnam to five. In addition, we identified three skulls or partial skulls of the dugong (Dugong dugon) in varying conditions, documenting their historical presence in an area where they are no longer present. These records further underscore the importance of whale temples both as places of historical culture and reverence, and important repositories of biodiversity data, from which information on former and current marine mammal distributions can be derived.