Technical report – NESP Marine Biodiversity Hub (July 2015 to June 2021)

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Feutry P, Laird A, Davies CL, Devloo-Delva F, Fry G, Johnson G, Gunasekara RM, Marthick J, Kyne PM (2021) Population structure of Narrow Sawfish Anoxypristis cuspidata across northern Australia. Report to the National Environmental Science Program Marine Biodiversity Hub. CSIRO, Charles Darwin University, and NPF Industry Pty Ltd.


This report is aimed at fishery and threatened species managers, and industry. Defining management units is critical for the globally Endangered Narrow Sawfish Anoxypristis cuspidate, and genomic approaches were used to analyse the species population structure across northern Australia. Samples were obtained from bycatch of commercial fisheries in collaboration with the Northern Prawn Fishery. Barriers to gene flow were evident between all regions where there were more than three samples, demonstrating female philopatric behaviour at finer spatial scales than previously suspected. In contrast, no evidence of population structure was detected using nuclear markers, suggesting male-biased dispersal. Sampling of neonates in nursery areas would help characterise the species philopatric behaviour. Results indicate that each region should be treated as a discrete management unit, with risk of population depletion if local bycatch mortality was to exceed the species biological productivity.

Type of publication Technical report
Year of publication 2021