Research and initiatives
Crocodiles are shy, well-camouflaged and mobile, which makes them a challenge to study. We take advantage of our regular interaction with crocodiles to run a number of research projects. Knowing more about crocodiles helps us develop tools and strategies to make our work safer and more efficient and provide policymakers and the community with the most accurate information, helping protect Queenslanders from harm.
Crocodile Monitoring Project
This ongoing study consists of comprehensive vessel and helicopter surveys of north Queensland’s major river systems. It provides a snapshot of the number and biomass of Queensland’s crocodile population and allows us to compare it to previous studies, showing population changes over time. This information helps inform future policy and management actions.
Queensland Estuarine Crocodile Monitoring Program 2016–2019
From 2016 to 2019, the department conducted a comprehensive monitoring program of the estuarine crocodile population across its range in Queensland. During 2020, we compiled and analysed data collected through this program and compared these to historic data to assess how the population had changed in size, distribution, density, and size class structure over time–using results collected from as far back as 1979. Further information about this program is available in the key findings report and the comprehensive technical report.
Technical report:
Download the full version of the technical report:
- Estuarine Crocodile Population Monitoring in Queensland (1979–2019) Technical Report (PDF, 354MB) - Please note this is a large file and may take time to download.
Or browse sections of the report:
- Appendix 1—Individual catchment and river maps, and survey transect comparisons, for selected rivers surveyed by spotlight in Queensland since 1979
- Appendix 2—Individual catchment and river maps for other rivers surveyed (PDF, 230MB) - Please note this is a large file and may take time to download.
- Appendix 3—Survey results for all waterways and survey years in Queensland ordered by date
- Appendix 4—Details of Methods
- Appendix 5—Details of common transects analysis methods
- Appendix 6—Report on an aerial survey of estuarine crocodile nesting habitat on the Proserpine River and Goorganga Plains
- Appendix 7—Crocodiles in the Lakefield-Rinyirru waterholes
- Appendix 8—Mapping the extent of crocodile habitat in Queensland
- Appendix 9—Hierarchical naming system for the Queensland survey transects .
Detection and Deterrent Project
In world-first research, departmental wildlife officers are examining the way crocodiles communicate through sounds, with early investigations revealing a surprising complexity of vocalisations. The application of this new knowledge could lead to innovative techniques to attract or repel crocodiles.
The department is also exploring how using multi-beam sonar technology together with image recognition software can detect crocodiles in an area and alert authorities of their presence. Our aim is to deploy this technology using a clever buoy system, which also records other environmental data (temperature, wind, humidity), to determine when and why crocodiles move into areas frequented by people.
Movement and DNA Project
Decades of satellite tracking have given us a solid idea of how crocodiles use and move through river environments, but what about oceans? The department is currently exploring this new frontier of crocodile habitat use by attaching satellite trackers to animals in the Torres Strait.
Wildlife officers have also been collecting DNA samples from crocodiles and analysing them to determine the relatedness and connectivity of the population in Queensland. These two parts of the project work help paint a picture of crocodile movement in Queensland, and between other populations nearby. The information gathered may directly impact how we manage crocodiles into the future.
Crocodile genetics research report
The genetic structure and connectivity of the estuarine crocodile (Crocodylus porosus) in Queensland 2018–2020 study redefines what is known about estuarine crocodiles in Queensland and more broadly.
Based on over two decades of movement studies, it was believed that estuarine crocodiles could move everywhere and anywhere.
The results of this genetics study have redefined what is known about estuarine crocodiles in Queensland and the species more generally.
It provides an understanding about where crocodiles in Queensland are from (source), where they go (sink), and how far they travel.
This knowledge helps to inform more efficient and effective management and reduce the threat to public safety.
Key facts
- The estuarine crocodile population within Queensland can be described as six sub-populations.
- Most crocodiles remain close to their place of birth with 90% of crocodiles dispersing less than 50km, leading to localised populations.
- There is evidence of historical and recent movement of crocodiles between adjacent sub-populations with connectivity declining with distance.
Find out more
In 2018, the Queensland Government began a long-term project to study the movements of Queensland’s saltwater (estuarine) crocodile population using DNA.
In 2018, the Queensland Government began a long-term project to study the movements of Queensland’s saltwater (estuarine) crocodile population using DNA.
