Abstract
The viability of spatially structured populations depends on the abundance and connectivity between subpopulations of breeding adults. Yet, for many species, both are extremely difficult to assess. The speartooth shark is a critically endangered elasmobranch inhabiting tropical rivers with only three adults ever recorded in Australia. Close-kin mark-recapture models, informed by sibling pairs among 226 juveniles, were developed to estimate adult abundance and connectivity in two Australian river systems. Sixty-eight sibling pairs were found, and adult abundance was estimated at 892 for the Adelaide River and 1128 for the Alligator Rivers. We found strong evidence for female philopatry, with most females returning to the same river to pup. Adelaide River males appear largely philopatric, whereas Alligator Rivers males are highly connected to the Adelaide River. From only 4 years of sampling, our results demonstrate that juvenile-only kin pairs can inform simultaneous estimates of abundance and connectivity in a rare and threatened species.
| Original language | English |
|---|---|
| Article number | eadd1679 |
| Number of pages | 7 |
| Journal | Science Advances |
| Volume | 8 |
| Issue number | 51 |
| DOIs | |
| Publication status | Published - 21 Dec 2022 |
Bibliographical note
Funding Information:Acknowledgments:W ethankM.BravingtonforCKMRdevelopmentanddetailedcomments on an early version of this manuscript. W e are also grateful to two anonymous referees whose inputledtosignificantimprov ements. P .Grewe,N.Bax,M.Douglas,andT .Saundersprovided project development and direction. W e thank Kakadu National Park staff, rangers, and Traditional Owners, and all volunteers who assisted in the field. Funding: This work was undertakenfortheMarineBiodiversityHub,acollaborativepartnershipsupportedthrough funding from the Australian Government’s National Environmental Research Program (NERP) andNationalEnvironmentalScienceProgram(NESP).Authorcontributions:T .A.P .andR.M.H. conceivedthepopulationmodelforthestudydesignedbyR.D.P ., P .F ., andP .M.K. Fieldworkand samplecollectionwerebyP .M.K., R.D.P ., G.J.J.,andP .F .R.M.H.andT .A.P .implementedthe populationmodelcodeandconductedanalysis.P .F ., J.R.M.,andR.M.G.carriedoutthe molecularwork.P .F .andR.M.H.analyzedgenotypedata.T .A.P .wrotethemanuscriptwithinput fromallotherauthors.Competinginterests:Theauthorsdeclarethattheyhavenocompeting interests.Dataandmaterialsavailability:Alldataneededtoevaluatetheconclusionsinthe paperarepresentinthepaperand/ortheSupplementaryMaterials.
Funding Information:
We thank M. Bravington for CKMR development and detailed comments on an early version of this manuscript. We are also grateful to two anonymous referees whose input led to significant improvements. P. Grewe, N. Bax, M. Douglas, and T. Saunders provided project development and direction. We thank Kakadu National Park staff, rangers, and Traditional Owners, and all volunteers who assisted in the field. This work was undertaken for the Marine Biodiversity Hub, a collaborative partnership supported through funding from the Australian Government’s National Environmental Research Program (NERP) and National Environmental Science Program (NESP).
Publisher Copyright:
Copyright © 2022 The Authors, some rights reserved.
