A rock painting of a sawfish
Rock art depicting a Largetooth Sawfish on Revolver Creek, Northern Territory. Image: Peter Kyne

Australia’s northern rivers and estuaries are important to sustaining sawfish and river shark species listed under Australia’s Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). This project will provide the Department of the Environment with information to improve management and facilitate the recovery of these species.

Acoustic telemetry, molecular research, life history studies and Indigenous engagement and education will be central to determining the status of threatened river sharks, and establishing monitoring, management and protection. Following are the key research activities.

Monitoring and understanding

More than 200 tagged animals will be monitored (via an acoustic array established in earlier research) for mortality estimates, movement patterns and habitat use, acoustic receiver arrays will be designed to measure long term movement and mortality in NT, QLD and WA rivers, and statistical methods developed for estimating annual juvenile mortality.

Thirty neonate Glyphis glyphis (Speartooth Sharks) will be tagged for mortality estimates and large sub-adult G. glyphis will be tagged to investigate adult distribution, reproductive philopatry and mortality (Adelaide River) and the age structure of G. glyphis will be determined for demographic models.

G. garricki (Northern River Shark) tissue samples will be collected in unsurveyed NT habitat (including the Daly, Finniss, Fitzmaurice, Victoria, Keep rivers) and in WA (Cambridge Gulf, King Sound) in partnership with Indigenous Ranger Groups, Murdoch University and NT Fisheries. G. garricki population structure will be examined and close-kin mark recapture used to establish a lower bound population size estimate.

Marine Biodiversity Hub research on habitat use, long-term movements and biologically important areas will be synthesised and recovery-directed research prioritised, and new information will be provided for updating the EPBC status of river sharks.

Indigenous partnerships for management

Key components of this project are being undertaken in partnership with Indigenous organisations, communities and ranger groups. Partnerships will assess Indigenous cultural use and knowledge of sawfish, and develop a sawfish education package for communities.

The Northern Australian Indigenous Land and Sea Management Alliance is a project partner and Indigenous land councils will be consulted to evaluate engagement and partnership opportunities.

Malak Malak Rangers (NT) and Dambi-Mangari Rangers (WA) among other ranger groups are assisting with field research, and protocols and methodologies are being developed for an annual Malak Malak Pristis pristis (Largetooth Sawfish) survey.

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