Steve Irwin began formal crocodile research in 1996. His capture and study techniques remain world’s best to this day. Today Australia Zoo staff run world-renowned research projects to preserve and understand this amazing species.
In 2007 the Steve Irwin Wildlife Reserve was established on the Cape York Peninsula. The 135 hectare reserve borders the upper reaches of the Wenlock River and provides an excellent platform to carry out scientific research on the river. The Wenlock River possesses the highest diversity of fish species of any river system in Australia, as well as a healthy population of estuarine crocodiles. Its floodplains form extensive suitable habitat for nesting females, and the Wenlock functions as a crocodile rearing stockyard for other river systems.
During August of 2008, the team captured and tagged 15 adult crocodiles (11 males and 4 females) from the Wenlock River. A miniature electronic device was implanted under the skin of these animals and they were released back into the river. These tags have enabled us to track the movements of these particular crocodiles over the next ten years. The signal transmitted from each receiver is recorded by underwater receiving stations. At the time, we had deployed 20 receivers covering a 64.3km stretch of the Wenlock River.
In 2009 the team added more receivers to the array, again greatly increasing the size of the study area and the data collection from our tagged crocodiles.
The 2010 expedition to the Wenlock River, tagged another 30 crocodiles, again broadening the size and depth of the sample group for the continuing study of these prehistoric creatures, as well as additional underwater listening receivers in popular swimming areas frequented by the locals.
During August of 2011 the croc research team caught a further 22 crocs, and has now tagged 86 crocodiles in this ongoing research project, with 26 crocs also having been satellite tagged since the program’s inception. In a first for the team, the researchers began trials of an accelerometer attached to the nuchal fold of a croc. The information gathered from the new device will help researchers graph intensity of movement of the crocs, and is hoped to indicate how regularly the implanted crocs are feeding. The research has begun to reveal the movements between the ‘wet’ and ‘dry’ season for the estuarine crocodiles, which tend to move out of the Wenlock River and into the side creeks and swamps during the ‘wet’. It is also the first year that researchers have been taking blood and tissue samples from the crocs for isotope analysis, to reveal further information about the crocodiles short and long term diets.
This project is still very much in progress and the research team are still learning much about the Wenlock River and its crocodile inhabitants.