On September 20, the reporter learned from the Institute of Deep-Sea Science and Engineering of the Chinese Academy of Sciences (hereinafter referred to as the Institute of Deep-Sea Science of the Chinese Academy of Sciences) that the "Seventh South China Sea Deep Dive/Pelagic Cetacean Scientific Expedition" organized by the Marine Mammal and Marine Bioacoustics Laboratory completed all the scientific research tasks and returned to Sanya recently. The scientific expedition has yielded fruitful results, and the researchers have further confirmed through the investigation that some waters of the South China Sea have rich diversity of cetacean species, and a large number of deep-diving and open-sea cetaceans inhabit the deep sea areas of the South China Sea.
The voyage lasted 18 days and covered a distance of more than 3,300 kilometers, and the investigation area was mainly concentrated in the waters of the continental slope, seamounts and troughs in the northern waters of the South China Sea. On the basis of the previous six expeditions, the diversity, population status and distribution patterns of cetaceans in the South China Sea were further investigated by a combination of visual investigation and passive acoustic monitoring, supplemented by environmental DNA collection. During the expedition, researchers witnessed a total of 37 groups of deep-diving and open-sea cetaceans, including 28 groups of deep-diving cetaceans, and obtained a large number of cetacean pictures, videos and audio materials through video shooting and animal vocalization records.
After preliminary analysis of the investigation results, the researchers found that there were at least 12 species of cetaceans witnessed on this voyage, including 9 deep-diving/open-sea cetacean species, including sperm whales, short-limbed pilot whales, melon-headed whales, Wright's dolphins (flower whales), Freund's dolphins, tropical spotted dolphins, long-nosed spinner dolphins, rough-toothed dolphins and bottlenose dolphins. 1 species of baleen whale.
Li Songhai, a researcher at the Institute of Deep Sea Research of the Chinese Academy of Sciences, said that compared with the previous six voyages, this voyage not only further accumulated ecological, acoustic and behavioral data of common deep-diving cetacean species in the South China Sea, such as sperm whales, Freund's dolphins, and short-limbed pilot whales, but also expanded the distribution range of cetacean species such as bottlenose dolphins, melon-headed whales, and rough-toothed dolphins in the South China Sea. In addition, it is particularly noteworthy that this voyage has added a field record of baleen whales in the South China Sea to obtain accurate location and habitat information.
Relevant data records show that there are more than 30 species of cetaceans that have been found in the South China Sea, and this area is the most abundant sea area for cetacean biodiversity on the mainland. However, apart from historical whaling records, information on some stranded cetaceans, and ecological surveys of a few nearshore species, such as the Chinese white dolphin, research and conservation of cetaceans in the South China Sea, especially in the deep sea areas of Xisha, Zhongsha, Dongsha and Nansha, was blank until 2019. So far, the Institute of Deep Sea Research of the Chinese Academy of Sciences has organized seven "South China Sea Deep Diving/Pelagic Cetacean Expeditions", which has gradually filled a number of gaps in the international understanding of cetaceans in the South China Sea, and provided a scientific basis for the mainland to protect the rare and endangered marine animals represented by cetaceans in this area in the next step.
Li Songhai said that through continuous cetacean scientific research in the South China Sea, researchers have gradually grasped the composition, diversity and geographical distribution characteristics of cetacean species in the South China Sea, and then faced the world's cutting-edge scientific and technological issues related to cetaceans. In the future, researchers will explore scientific issues such as adaptive evolution, behavioral ecological characteristics, ecological functions, habitat characteristics and potential threat factors of cetaceans in the South China Sea.
(Photo courtesy of the interviewee)
Source丨Science and Technology Daily