Euryhaline elasmobranchs (sharks and rays) are highly vulnerable to anthropogenic threats due to their restricted habitat. The rivers of Rinyirru (Lakefield) National Park (CYPAL) in Cape York, Queensland, are inhabited by three species of euryhaline elasmobranchs: freshwater whiprays Urogymnus dalyensis, bull sharks Carcharhinus leucas and freshwater sawfish Pristis pristis, but their distribution and movement patterns are poorly understood.
Collaboration with Aboriginal Land and Sea Rangers led to the adaptation of existing methodology to account for local ecosystem parameters, including extreme environmental conditions, and seasonal changes in water levels. Indigenous Rangers provide critical insights into the study area, including identification of acoustic receiver deployment sites, to best mitigate wet season impacts. This partnership between researchers and Aboriginal Land and Sea rangers empowered rangers to independently manage receiver deployment and to tag elasmobranch via specialised external acoustic tags, thus increasing sample size and facilitating ongoing monitoring.
Since 2023, 4 C. leucas, 3 U. dalyensis, and 1 P. pristis have been captured and their movements tracked via a network of 18 acoustic receivers. This study highlights the significance of integrating Indigenous knowledge and collaboration into scientific research to enhance our understanding of the distribution and ecology of elasmobranchs in remote regions.