Dugong Research at Burrum Heads and hervey Bay

http://www.reef.crc.org.au/resprogram/programA/C1-4-3-2S.htm

This project will quantify fine-scale foraging activities of dugongs in the Great Barrier Reef region of Australia in order to develop a grazing model that will describe where and when dugongs feed, why they choose those areas and the costs and benefits involved in doing so.

Dugongs are seagrass specialists and understanding the interaction between dugongs and their food supply is crucial to their conservation. The seagrasses on which dugongs depend are extremely variable in abundance, community structure and chemical composition over small and large spatial and temporal scales.
Studying the interaction between dugongs and their seagrass food requires knowledge of the movements and diving behaviour of dugongs at scales relevant to both dugongs and managers. This has not been possible in the past because of the difficulties of direct observation of dugongs and the low resolution of telemetric equipment.
This project is a fine-scale study that capitalises on recent developments incorporating accurate GPS technology into tracking equipment to monitor the habitat use of up to 60 dugongs at a resolution of a few metres, several times each hour throughout the day. This will provide the ability to model and map dugong habitat use in the inshore waters of the Great Barrier Reef and adjacent Hervey Bay and to assess the relative importance of different seagrass meadows and parts of meadows to dugongs at scales that are suitable for informing policy on the management of human activities including boating, traditional hunting, and commercial gill netting.
In September 2003, the first wholly successful deployment of GPS tracking devices on dugongs was completed. James Sheppard led a team who deployed tracking devices and dive data loggers on seven dugongs (two females, five males) at Burrum Heads in Hervey Bay. James returned to JCU with all the tracking devices loaded with data. While the data has not yet been downloaded and fully analysed, a portion of it was uploaded via satellite while the tracking devices were still on the dugongs. Even with that limited data set, some surprising insights into dugong movements have been gained.
The first is confirmation of the connection between the Hervey Bay study site and the Great Barrier Reef. Two dugongs travelled north out of the Bay. One made a return journey to Great Keppel Island, staying there for a little over a week, while another headed 500km north to Clairview where it remained for the duration of the tracking period.
The second important finding was identifying the tip of Fraser Island as an important winter habitat for dugongs. Four of the seven tracked dugongs visited the area, travelling over 70km from the capture point. This area had not previously been recognised as dugong habitat. Further insights will be gained as we analyse the tracking data in detail and link it to our studies of seagrass quality and abundance. With this success behind us we are eagerly looking forward to our follow up trips in Hervey and Shoalwater Bays leading into 2004.