Davies C, Tothill T, Meeuwig JJ and Kyne PM (2022) Garig Gunak Barlu National Park Green Sawfish (Pristis zijsron) aggregation surveys. National Environmental Science Program Marine Biodiversity Hub. Charles Darwin University.
Overview
This report details two surveys of Green Sawfish (Pristis zijsron) at two sites in Garig Gunak Barlu National Park in the Northern Territory. Weather conditions and limited water clarity restricting usable video footage from drones at one site (Lidarnardi) during survey 2. The use of Baited Remote Underwater Videos were unsuccessful. Drones recorded Green Sawfish on 88% of survey days and 30% of transect flights. Sawfish numbers ranged from 1–8 individuals per transect and density from 3.8–30.5 per hectare (the highest density of sawfish ever reported). Sawfish ranged from 57–167 cm total length (TL), with most 60–100 cm TL, suggesting a nursery area. The surveys confirmed the presence of juvenile Green Sawfish in intertidal waters of the national park, suggesting the park waters represents critical habitat, and provides the species some refuge from major threats. However, similar inshore intertidal habitat is not well represented in northern Australian protected areas.
