Project Manta updates March 2010

Lady Elliot Island Field trip
Once again, we had an amazing field trip at LEI in early February 2010 with our EarthWatch volunteers. We encountered 25 mantas and identified 18 of them including 6 new individuals.
During this trip we also tested our acoustic receivers placed all around the island using a special acoustic tag (called range test tag). We tested whether the receivers can detect the signal from the acoustic tag continuously over a 24hour period and to what range the receiver can detect the signal (around 500m).
We also downloaded the data from the listening stations, which revealed that some of the tagged mantas have been hanging around the island since June with short periods of absence while others totally disappeared after a certain period of time.
This is important as it shows that some mantas may be resident to Lady Elliot Island and use the habitat all year around while others may undertake longer migrations. A big thank you to AATAMS for access to equipment and expertise over the last year.
We also collected data on the temperature, current direction and current strength around the island relative to tidal cycles. This allowed us to confirm that manta rays tend
to start feeding during the outgoing tide at LEI, when the current brings important concentrations of plankton to the island. Several mantas were sighted feeding during the trip and we had the opportunity to swim with them and observe their feeding behaviour.
In addition, plankton tows were conducted all around the island to monitor the plankton community in relation to the different tidal scenarios. Plankton tows were also conducted in the feeding trails of mantas, which shall help us to determine food preferences of these giants.
It was a very busy trip, but it didn’t stop us from having a lot of fun. The baby turtles hatching was an amazing sight to behold!
Our next trip to LEI will be from the 20th of June to the 3rd of July. It will be the peak season for manta rays aggregation. On the program:

Lots of photos to ID as many mantas as possible (diving and snorkelling)
Lots of current, temperature and other parameter measurement around the island
Lots of plankton collection
Taking tissue sample from manta rays (biopsy) for genetic and diet determination
Documentary filming
Acoustic receiver deployment around the island at specific sites
Satellite tag deployment on mantas

If you would like to become a volunteer for Project Manta at Lady Elliot Island and be part of a great adventure, please contact EarthWatch Australia :
http://www.earthwatch.org/australia/exped/townsend.html
Contact Andy Donnelly at scienceprogram@earthwatch.org.au

We are looking forward hearing from you

Best,

The Project Manta Team
Lydie Couturier
Fabrice Jaine
Dr Kathy Townsend
Prof Mike Bennett
Dr Scarla Weeks
Dr Anthony Richardson