Observations were made on one eye from a Longman’s beaked whale Indopacetus pacificus, which was probably one of the least known extant cetaceans. The whale died shortly after swimming aground on the coast in the Nis...Observations were made on one eye from a Longman’s beaked whale Indopacetus pacificus, which was probably one of the least known extant cetaceans. The whale died shortly after swimming aground on the coast in the Nishikata Beach, Sendai-shi, Kagoshima-ken Prefecture, Japan, on July 26, 2002. It was a mature female with body length 6.45 m. This paper documented the basic structural characteristics of her visual organ of the whale in order to better understand this animal.展开更多
Beaked whales represent around 25%of known extant cetacean species,yet they are the least known of all marine mammals.Identification of many Mesoplodon species has relied on examination of a few stranded individuals.P...Beaked whales represent around 25%of known extant cetacean species,yet they are the least known of all marine mammals.Identification of many Mesoplodon species has relied on examination of a few stranded individuals.Particularly,the ginkgo-toothed beaked whale(Mesoplodon ginkgodens)and Deraniyagala’s beaked whale(Mesoplodon hotaula)are among the least-known of beaked whale species,without confirmed sightings of living individuals to date.We present a sighting of 3 free-ranging individuals of M.ginkgodens/hotaula whale from a dedicated marine mammal vessel survey carried out in the South China Sea in April and May 2019.Photographic data(301 photographs)from the sighting were compared to photos of fresh stranded ginkgo-toothed beaked whale and Deraniyagala’s beaked whale from both historical and unpublished records.We found that free-ranging M.ginkgodens and M.hotaula individuals can be easily distinguished from other Mesoplodon species due to differences in melon and gape shapes and coloration patterns.However,accurate at-sea differentiation of M.ginkgodens and M.hotaula may not be possible due to high similarity in both coloration and scarring patterns.In addition to our photo-identification data,we collected what we believe to be the first preliminary descriptions of surfacing behavior and diving patterns of one of these species.Finally,the presence of scars possibly caused by fishing gear or marine litter raises concerns about anthropogenic impacts and conservation of these poorly known species.展开更多
基金the National Science Museum,Tokyo 169-0073,JapanNNSF of China (No.40376042)Natural Science Foundation of Shandong Province (No.Y2007D75)
文摘Observations were made on one eye from a Longman’s beaked whale Indopacetus pacificus, which was probably one of the least known extant cetaceans. The whale died shortly after swimming aground on the coast in the Nishikata Beach, Sendai-shi, Kagoshima-ken Prefecture, Japan, on July 26, 2002. It was a mature female with body length 6.45 m. This paper documented the basic structural characteristics of her visual organ of the whale in order to better understand this animal.
基金supported by the National Key Research and Development Program of China(Grant number 2016YFC0300803)the National Natural Science Foundation of China(41406182,41306169 and 41422604)+1 种基金the biodiversity investigation,observation and assessment program(2019-2023)of Ministry of Ecology and Environment of ChinaOcean Park Conservation Foundation Hong Kong(MM02-1516,AW02-1920).
文摘Beaked whales represent around 25%of known extant cetacean species,yet they are the least known of all marine mammals.Identification of many Mesoplodon species has relied on examination of a few stranded individuals.Particularly,the ginkgo-toothed beaked whale(Mesoplodon ginkgodens)and Deraniyagala’s beaked whale(Mesoplodon hotaula)are among the least-known of beaked whale species,without confirmed sightings of living individuals to date.We present a sighting of 3 free-ranging individuals of M.ginkgodens/hotaula whale from a dedicated marine mammal vessel survey carried out in the South China Sea in April and May 2019.Photographic data(301 photographs)from the sighting were compared to photos of fresh stranded ginkgo-toothed beaked whale and Deraniyagala’s beaked whale from both historical and unpublished records.We found that free-ranging M.ginkgodens and M.hotaula individuals can be easily distinguished from other Mesoplodon species due to differences in melon and gape shapes and coloration patterns.However,accurate at-sea differentiation of M.ginkgodens and M.hotaula may not be possible due to high similarity in both coloration and scarring patterns.In addition to our photo-identification data,we collected what we believe to be the first preliminary descriptions of surfacing behavior and diving patterns of one of these species.Finally,the presence of scars possibly caused by fishing gear or marine litter raises concerns about anthropogenic impacts and conservation of these poorly known species.
