Morphological abnormalities in wild animals can be indicators of the underlying health of a population and may be determined through routine photographic surveys.Here,we assess unusual rostrum conditions in Indian Oce...Morphological abnormalities in wild animals can be indicators of the underlying health of a population and may be determined through routine photographic surveys.Here,we assess unusual rostrum conditions in Indian Ocean humpback dolphins(Sousa plumbea)inhabiting South African coastal waters to understand the rate of prevalence of abnormal rostrums and formulate hypotheses on potential causes.Photographic data were collated from sys-tematic boat surveys and opportunistic sightings,obtained between April 1998 and March 2021 in various regions along the South African coast.Overall,31 unique individuals were found with abnormal rostrum conditions,vary-ing from slight misalignments to severe wounds and/or aberrant morphologies.In most cases,injuries were likely caused by natural events during the animal’s life history such as interactions with sharks and/or reef-associated hunting strategies.Mark–recapture data indicated that individuals had survived with these injuries for up to 10 years.This study reports the highest incidence of rostrum abnormalities in the species.As numbers reflect only those that have survived their injuries,they are considered a minimum estimate.A better understanding of the cause(s)of these injuries is important given the endangered status of this species.展开更多
基金This research was possible due to the collaboration of the SouSA consortium members that involve multiple institutions.This study was supported by a National Research Foundation grant awarded to T.G.(Grant number:116047)including G.F.’s postdoctoral fellowship and S.D.’s PhD scholarship.O.A.V.-F.was funded by a Nelson Mandela University Postgraduate Research Scholarship(2015-2018)and supported by the MARISCO project(FAIN:2019902/KK2153)+6 种基金which is funded by the Belmont Forum(2021/2022)Research was conducted under a series of research permits issued by the Department of Environment Forestry and Fisheries(and its predecessors)to S.E.(RES 2015/94 to 2021/26)O.A.V.-F.(RES 2013/67 AND RES 2015/79)This study was carried out and under ethics clearance from the University of Pretoria Animal Use and Care Committee permit(EC074-15)the Stellenbosch University AUCC(ACU-2021-13330)by Nelson Mandela University animal ethics clearance(A13-SCI-ZOO-001)grateful to Orca Foundation for field work assistance,as well as for the Rufford Foundation,the Society for Marine Mammalogy,and the German Society for Dolphin Conservation(Gesellschaft zur Rettung der Delphine)for financial support in Plettenberg Bay(2013-2015).
文摘Morphological abnormalities in wild animals can be indicators of the underlying health of a population and may be determined through routine photographic surveys.Here,we assess unusual rostrum conditions in Indian Ocean humpback dolphins(Sousa plumbea)inhabiting South African coastal waters to understand the rate of prevalence of abnormal rostrums and formulate hypotheses on potential causes.Photographic data were collated from sys-tematic boat surveys and opportunistic sightings,obtained between April 1998 and March 2021 in various regions along the South African coast.Overall,31 unique individuals were found with abnormal rostrum conditions,vary-ing from slight misalignments to severe wounds and/or aberrant morphologies.In most cases,injuries were likely caused by natural events during the animal’s life history such as interactions with sharks and/or reef-associated hunting strategies.Mark–recapture data indicated that individuals had survived with these injuries for up to 10 years.This study reports the highest incidence of rostrum abnormalities in the species.As numbers reflect only those that have survived their injuries,they are considered a minimum estimate.A better understanding of the cause(s)of these injuries is important given the endangered status of this species.
