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Endangered sawfish populations monitored in the Kimberley

A team of scientists have been monitoring populations of the endangered freshwater sawfish in the Kimberley.

The project, funded by the State NRM, aimed to increase the understanding of the ecology and habitat utilisation of Fitzroy River Freshwater Sawfish (Pristis pristis).

Working with Indigenous rangers and other community members, Murdoch University’s Freshwater Fish Group and Fish Health Unit tagged over 200 sawfish throughout the Fitzroy River from Derby to Fitzroy Crossing since 2009.

Dr David Morgan, senior research leader of the Freshwater Fish Group and Fish Health Unit at Murdoch University, said Freshwater Sawfish populations have declined on a global basis.

“Recent evidence suggests that the species is in decline, with the largest known population in Western Australia, which utilises the Fitzroy River as a nursery,” Dr Morgan said.

The increasing focus on the resources of the river and surrounding country to develop areas for irrigation and increased production is also impacting on the ecosystems that support the species.

The project, which was finalised earlier this year, continued from previous work in 2003 and between 2005 and 2009, using a conventional and acoustic tagging program involving the Nyikina-Mangala Rangers as well as Bunuba and Gooniyandi participants.

“Community awareness of the threats on the survival of the species were enhanced through participation in field work and through the delivery of presentations to community member,” Dr Morgan said.

Old rostra (saws) and tissue samples were collected for genetic analysis, which will allow comparisons to be made with populations elsewhere and to the importance of the Fitzroy River population.

The high flows of 2011 saw a boom in recruitment of sawfish, with some 150 sawfish tagged in a single pool.

“Many tagged sawfish that were caught by the public were phoned in, and a Team Sawfish sent out as a reward,” Dr Morgan said.

Dr Morgan said the team continues to tag sawfish in the river as part of the environmental offsets funded through WAMSI from Chevron Australia.

The work will lead to an increased understanding of the behavioural patterns of the freshwater sawfish that will enable setting clear actions to increase the preservation of the species.

“The next goal is to determine the impacts of barriers on the river for sawfish migration,” he said.

For more information, contact David Morgan, Freshwater Fish Group  Centre for Fish & Fisheries Research, Murdoch University Email: d.morgan@murdoch.edu.au Tel:  08 9360 2813

Photo: Team Sawfish: Bunuba, Gooniyandi and Nyikina-Mangala Rangers with Murdoch University Freshwater Fish Group staff at Geikie Gorge