One of my highlights during my scholarship year was spending a month volunteering for the Earthwatch program: Whale Sharks of Ningaloo Reef.
So it was great that after presenting my scholarship video and officially handing over the Australasian scholarship to Matt, I found mysaelf flying back from New York City, one day at home and then on another plane, this time headed straight back to the red dust of Exmouth and the turquoise waters of Ningaloo Reef.
Brad Norman the founder and project coordinator of the research, education and conservation group, ECOCEAN, had invited me back to work as a team leader for this year’s Earthwatch volunteers. This involves spending days on the local tourist industry boats – of which there are seven working out of Exmouth and three from Coral Bay, collecting identification photographs of the sharks and uploading these to the ECOCEAN Whale Shark Photo-identification Library.
Using the unique spot pattering behind the gill slits and above the pectoral fins individual sharks can be identified allowing non-invasive and accurate estimates of the shark’s population size and movement patterns. Spot pattern data at Ningaloo goes back as far as 1995 and currently has identified over 500 Different whale sharks visiting Ningaloo Reef.
With an unprecedented number of photographs and video collected from the public and tourism industry at Ningaloo Marine Park recently, ECOCEAN was able to create statistical models demonstrating a modestly increasing annual population visiting Ningaloo. But this year I witnessed something special. From all accounts 2009 was the best season on record! Sharks were in abundance and tour operators had no problem finding sharks to entertain the growing number of tourists.
From Ningaloo alone, latest figures have shown 193 whale sharks identified this season, not including the sharks that have managed to hide from the cameras! We have also been seeing an increased number of smaller whale sharks feeding at the reef and returning in subsequent years. This gives me optimism for shark conservation, especially when we know the plight facing the many other species of sharks around the world!
To get some idea of shark size and population structure, people have traditionally estimated shark size or, on the odd occasion with cooperative sharks used a tape measure to record their length. In recent years, stereo video has become the most accurate and practical way to measure fish underwater. So for the past three years, ECOCEAN, in association with Murdoch University, have invested in a diver operated stereo video camera system to accurately measure the shark’s size.
This was my job. After learning about the technology last year, I was ready to measure some beasts! Saying that, pushing a 20 kg camera frame through the water following a swimming shark was challenging at times, especially in rough conditions! But this year I was able to measure 20 sharks, pushing the total to 38. Unfortunately no sharks have been remeasured yet, but with proof that many of the sharks are returning to Ningaloo every year, it is only a matter of time before we can start to get some accurate estimates of growth rates. Nevertheless the data collected now is enough for a scientific publication that I am currently working on with Brad and George Shedrawi.
Like any other oceanic creature, many mysteries will still remain about the whale shark. But with new technology, come new insights. So for the past two seasons, Brad Norman and Adrian Gleiss, a PhD student from Swansea University in the Wales, have been testing the use of ‘daily diary’ tags to find out what these magnificent creatures get up to when they are out of sight. This genius of a tag detects every movement of the shark in sub-second resolution by measuring 13 parameters eight times a second.
This was an exciting experiment and involved staying at a remote shearing station on the Ningaloo coastline, using two small vessels and our own chartered spotter plane to find the sharks. We got off to a slow start, tagging only one shark in 3 days, as the majority of the sharks had only recently moved up the coast towards Exmouth and were stuck further south.
After a decision to re-locate we eventually hit the jackpot on the last day tagging sharks up to 7.5m long with the remaining three tags. With the tags attached to the second dorsal-fin like a “clip-on” earring, the tags release after three days and float to the surface allowing us to relocate them using VHF radio antennas.
But that forms another problem. Searching the open ocean in a small boat looking for a small orange piece of foam was like the proverbial needle in a haystack. But we had trust in Adrian and he came up with the goods. With me skippering the boat at sunset and 5 miles off the Ningaloo coastline, We were able to find the tag and after a big swan dive from Adrian, we all celebrated with the WA equivalent of VB – an ice cold Emu Bitter!
The next day was easy picking up the other two floating tags without a problem, although there was still one $5000 tag out there. We gave up on it. The following week Brad received a phone call and someone had found the tag on a remote beach not far from where we tagged it! Once again – stoked!
The tags allowed us to reconstruct the movement of the sharks down to every wink of the eye and documented vertical movement of these giants. As sharks do not have a swim-bladder and are heavier than seawater, they are able to passively glide down searching for food and actively swim back to the surface. Furthermore, the tags revealed much more information including sudden bursts of activity, both at the surface and at depth, this may be indicative of lunge feeding, similar to many baleen whales, such as humpbacks.
This was a memorable trip and shows just what the scholarship can do. New friends and opportunities to visit beautiful parts of the world while gaining first hand experience and harnessing new technologies for future research.
Without the rush of the scholarship I had more time to experience the desert state, this stint in WA latested 3 months and during that time I was able to enjoy a few road trips, camping and some fantastic diving.
For a week I stayed with local underwater photographers, Ross and Mary Gudgeon, we did several dives together and Ross taught me a few new tricks to photography and Photoshop. I was then lucky enough to dive the world class Navy Pier with the best conditions ever! All the staff working there had never seen water of that clarity and there were fish absolutely everywhere including a few grey nurse sharks! I was stoked.
Back in Perth I attended an international fish biology conference, where I was awarded a very prestigious award! The D.D. François award, but that is a story for another time! I also spent some time at the Uni of WA analysing the stereo video footage of the whale sharks.
Now, I have decided to take on a PhD through UWA and just received a scholarship to study deepwater fish. I start in January before heading off to Guam and conducting fieldwork over there for several months looking at depth as a refuge from fishing pressure. Pretty exciting! So hopefully I will continue to blog on this site as there will sure be plenty of stories to come!
Best fishes, Steve
