The largetooth sawfish (Pristis pristis) can be found across the globe, and consists of four separate sub populations; the Western Atlantic, Eastern Atlantic, Eastern Pacific, and Indo-West Pacific (including northern Australia – spanning the Kimberley to Cape York Peninsula). The species was once considered common across many of these sub populations but has unfortunately undergone drastic population reductions. The largetooth sawfish is now thought to be locally extinct in many regions, and as such is listed as Critically Endangered under the IUCN Red List. The Kimberley region in north-Western Australia represents one of the last intact nurseries for the largetooth sawfish, however even within Australia the species is threatened and listed as Vulnerable under Australia's EPBC Act.
The species is biologically fascinating, both in appearance, due to its large rostrum (averaging between 17 and 24 teeth per side) which is used for predation and defence, and also in its ability to tolerate a wide range of salinities (euryhaline). The largetooth sawfish will spend the first three to four years of its life within freshwater systems growing to a length of approximately 3-4m, before then migrating into the estuarine and marine environments where they reach over 6m in length as an adult. Within the freshwater systems, the diet of the largetooth sawfish consists primarily of species found in the lower water column or benthic environment, such as the blue-catfish (Neoarius graeffei), and detritus. Recent research has furthered the understanding of habitat utilisation of the largetooth sawfish in the Fitzroy River (Whitty et al., 2009, 2017; Gleiss et al., 2017). Although key findings for the species were identified, such as habitat partitioning between age cohorts in the lower and tidal reaches of the river (Whitty et al., 2009), patterns of depth migration and thermal stratification of pools (Gleiss et al., 2017), recommendations for future research were made such as the collection of comprehensive fine-scale temperature data to further understand thermoregulatory behaviour and vertical migrations by largetooth sawfish. A great deal of work is still required to understand how this fascinating species and the Fitzroy system will respond to changes arising from climate change and water use in the catchment. Fun Facts!
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AuthorMy name is Garry and I am extremely passionate about the environment. I have completed my BSc. Conservation and Wildlife Biology with First Class Honours and have worked in the Environment sector since 2009. Archives
September 2019
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