Research on the impact of marine debris on marine turtle survival and behaviour: North east Arnhem Land, Northern Territory, Australia
Dhimurru turtle tracking report
Marine debris consists of any man made material that ends up in our oceans. Over 70 per cent of this biohazard is made up of derelict fishing nets termed "ghost nets" that have been accidently lost, deliberately discarded or simply abandoned at sea (Department of Natural Resources Environment and the Arts 2008). Other items such as rope, plastic, glass bottles, footwear, thongs and timber are among the next highest most discarded items (Department of Natural Resources Environment and the Arts 2008) and also pose a significant risk to wildlife.
Marine debris, and in particular ghost net, is an extremely dangerous phenomenon for marine animals. Marine turtles appear to suffer a great number of entanglements resulting in the injury and death of these key iconic and often endangered species. In the period of this report 4 marine turtles were recovered none released alive in 2007 and 4 released alive in 2008.
The second part to this report is concerned with the satellite tracking project undertaken by Dhimurru in conjunction with the partners identified in the preceding pages. Satellite tracking is a technique developed aimed at following the movements of individual turtles over long distances over several months. A specially designed instrument plots the animal's location, depth, direction of travel and length of time spent underwater. It then transmits this information to the researcher's computer via a satellite (NAILSMA 2006). These devices are glued to the turtle shell and can be expected to transmit data for up to 3 years (Hayes, G 2008). Three transmitters were deployed. One relayed very little information, one transmitting for several weeks and one transmitting for over three months and is continuing to present data.