Researchers are working with Indigenous rangers in the Northwest to identify ideal habitats of critically endangered freshwater sawfish in Western Australia’s Fitzroy River.

Freshwater sawfish are an iconic species of Australia’s north, which is home to nurseries of global importance.  These incredible animals, with their long rostrums, grow to around seven metres in length and are amongst the largest living fish.

Although sawfish numbers appear to be healthy in some small pockets of northern Australia, they have seen drastic decline globally, ranking them amongst the most endangered fishes worldwide.

Dr Morgan and Dr Gleiss have been identifying the environmental conditions that need to be considered in conservation and management decisions for the waterway. The team have been tagging the endangered animals with electronic tags to understand what they’re doing, where they’re going, how much water they need and how that impacts their growth.

The research aims to understand how variations in conditions in the river – like how big a wet season is or how much water is in the river at any time – impacts the ability of these fish to survive and grow to full maturity.

One of the studies revealed sawfish were considerably healthier in years with greater wet season river flows, allowing them to build a higher resilience to the long dry seasons that follow.

The data is already helping to inform the water resource management of the river, as the research team continue to work closely with the Department of Water and Environmental Regulation (DWER), providing evidence to inform water planning policy.

The goal is to balance the agricultural and economic needs of the communities that draw water from the Fitzroy River with realistic water targets that are not going to be detrimental to the animals. Now, only at certain thresholds will DWER allow water to be taken from the river.