A pioneering survey of deep‐diving and off‐shore cetaceans in the northern South China Sea

Abstract

A pioneering boat-based survey was conducted in 2019, to gather baseline information regarding the presence, composition, relative abundance, and spatial distribution of deep-diving and off-shore cetaceans in the northern South China Sea (SCS). A total of 27 sightings comprising at least 8 cetacean species were recorded during the 13-day survey, including 5 deep-diving species (i.e. Risso's dolphin [Grampus griseus], short-finned pilot whale [Globicephala macrorhynchus], sperm whale [Physeter macrocephalus], Cuvier's beaked whale [Ziphius cavirostris], and an unidentified beaked whale [either the ginkgo-toothed beaked whale, Mesoplodon ginkgodens, or Deraniyagala's beaked whale, Mesoplodon hotaula]), as well as 3 off-shore dolphins (i.e. pantropical spotted dolphin [Stenella attenuate], striped dolphin [Stenella coeruleoalba], and Fraser's dolphin [Lagenodelphis hosei]).With the exception of pantropical spotted dolphins, all other species were sighted and recorded at sea in the northern SCS for the first time. The pantropical spotted dolphin was the most frequently sighted species, comprising 30% of the total sightings. Deep-diving cetaceans were mainly sighted in the northern Xisha Archipelago, whereas off-shore dolphins were distributed across the survey area. The pantropical spotted dolphin was observed in aggregations of more than 100 individuals and nearly all encountered species included calves; these findings suggested that the survey area functions as an important feeding and calving ground for various cetacean species. This pioneering survey provides fundamental information regarding cetacean fauna in the northern SCS and highlights the need to strengthen research and conservation efforts concerning these species.

First live sighting of Deraniyagala's beaked whale (Mesoplodon hotaula) or ginkgo‐toothed beaked whale (Mesoplodon ginkgodens) in the western Pacific (South China Sea) with preliminary data on coloration, natural markings, and surfacing patterns

“…The scientific expedition was conducted onboard the 50‐m‐long RV Tian'e from April 26 to May 10, 2019 (for details, see Lin et al . 2020). The study area extended on the northern part of the South China Sea (Fig.…”

“…Rosso M, Lin M, Caruso F et al (2021). First live sighting of Deraniyagala's beaked whale (Mesoplodon hotaula) or ginkgo-toothed beaked whale (Mesoplodon ginkgodens) in the western Pacific (South China Sea) with preliminary data on coloration, natural markings and surfacing patterns.…”

Research on whales, dolphins, and porpoises

“…Of the 8 encountered species, 7 were recorded at sea in the northern South China Sea for the first time. Through using photographic data, Rosso et al (2021) identified a group of mysterious beaked whales from the field survey depicted by Lin et al (2021a). Photographic evidences showed that the mysterious beaked whales are either ginkgo-toothed or Deraniyagala's beaked whales (Mesoplodon ginkgodens or M. hotaula).…”

“…In this volume, Lin et al . (2021a) presented a first attempt to investigate deep‐diving and off‐shore cetaceans in the northern waters of South China Sea. This study presented a high diversity of cetacean species in the survey area.…”

“…(2021) identified a group of mysterious beaked whales from the field survey depicted by Lin et al . (2021a). Photographic evidences showed that the mysterious beaked whales are either ginkgo‐toothed or Deraniyagala's beaked whales ( Mesoplodon ginkgodens or M. hotaula ).…”