Peer Review #1 of "Diet and mitochondrial DNA haplotype of a sperm whale (Physeter macrocephalus) found dead off Jurong Island, Singapore (v0.1)" [peer_review]

2019 unpublished
Despite numerous studies across the large geographic range of the sperm whale (Physeter macrocephalus), little is known about the diet and mitochondrial DNA haplotypes of this strongly female philopatric species in waters off Southeast Asia. A female sperm whale found dead in Singapore waters provided the opportunity to study her diet and mitochondrial DNA haplotype. Here we report on the identification of stomach contents and mitochondrial DNA haplotype of this individual, and we include
more » ... nd we include coastal hydrodynamic modelling to determine the possible geographic origin of the whale. At least 28 species of prey were eaten by this adult female whale, most of which were cephalopods. The mesopelagic squids Taonius pavo, Histioteuthis pacifica, Chiroteuthis imperator,and Ancistrocheirus lesueurii made up over 65% of the whale's stomach contents. Plastic debris was also found in the whale's stomach. Based on the diet, genetics, and coastal hydrodynamic modelling that suggest an easterly drift of the whale carcass over several days, the dead sperm whale in Singapore probably originated from a pod in the Southern Indian Ocean. This study provides an increase in the understanding the diet and natural history of the sperm whale in Southeast Asia. The combined analyses of stomach contents, DNA, and hydrodynamic modeling could provide a context to future studies on the sperm whale strandings, and have broader applicability for other marine mammals in the region. Manuscript to be reviewed 21 Abstract 22 Despite numerous studies across the large geographic range of the sperm whale (Physeter 23 macrocephalus), little is known about the diet and mitochondrial DNA haplotypes of this 24 strongly female philopatric species in waters off Southeast Asia. A female sperm whale found 25 dead in Singapore waters provided the opportunity to study her diet and mitochondrial DNA 26 haplotype. Here we report on the identification of stomach contents and mitochondrial DNA 27 haplotype of this individual, and we include coastal hydrodynamic modelling to determine the 28 possible geographic origin of the whale. At least 28 species of prey were eaten by this adult 29 female whale, most of which were cephalopods. The mesopelagic squids Taonius pavo, 30 Histioteuthis pacifica, Chiroteuthis imperator, and Ancistrocheirus lesueurii made up over 65% 31 of the whale's stomach contents. Plastic debris was also found in the whale's stomach. Based on 32 the diet, genetics, and coastal hydrodynamic modelling that suggest an easterly drift of the whale 33 carcass over several days, the dead sperm whale in Singapore probably originated from a pod in 34 the Southern Indian Ocean. This study provides an increase in the understanding the diet and 35 natural history of the sperm whale in Southeast Asia. The combined analyses of stomach 36 contents, DNA, and hydrodynamic modeling could provide a context to future studies on the 37 sperm whale strandings, and have broader applicability for other marine mammals in the region.
doi:10.7287/peerj.6705v0.1/reviews/1 fatcat:wp47nvecrbd6hcyfygwpcmcwd4