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In an attempt to better understand what lures whale sharks so predictably every year to Ningaloo Marine Park in North Western Australia, scientists
from the Australian Institute of Marine Science (AIMS) have attached a “Crittercam” to a 7m whale shark. The camera, which was deployed earlier this year, was provided by the National Geographic Society and is designed to automatically disconnect after a period of time and float to the surface where it emits a
VHF signal allowing for a simple search and rescue operation to retrieve the valuable film within.
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The first attempt to attach the camera on a 5m shark failed. The shark took the “crittercam” straight to the sandy bottom and by rolling on its side managed to scratch the camera off. “After many months of planning it took no less than a minute and a half for the shark to figure out how to shed the camera” Dr
Meekan remarked. The second attempt yielded the same behaviour. "Clearly the sharks are not as dumb as we thought they were, and they obviously don’t want the tag attached," Dr
Meekan says. This behaviour is really interesting because it explains why the scientists had such problems in the past attaching the satellite tags to the sharks.
Following this unexpected discovery, Dr
Meekan and his team looked at the remora, a fish that hitches a ride on the sharks, to better understand where to place the camera on the shark, so that it was less likely to be scratched off.
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“Crittercam’s” torpedo shaped waterproof
casing is about two hand spans in length and is
more than just a video camera. It also has sensors
for measuring water temperature and depth. Photo Peter Nicholas |
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After several
failed attempts, the “crittercam” is finally
deployed on a 7m female whale shark. Photo Peter
Nicholas |
Armed with a better understanding of the shark’s behaviour, the team successfully deployed the camera on a 7m female. The video that emerges is "magic" says Dr
Meekan. "It’s like you’re holding onto the dorsal fin of the shark and it’s taking you for a dive”.
The AIMS team followed the shark along the bottom, watched it swimming over the contours, and the schools of fish playing around its head. “It doesn’t swim during a dive, but rather performs an enormous graceful glide gathering quite a bit of momentum before levelling out just off the bottom" recalls Dr
Meekan. This experiment proves that the “crittercam” can be used to monitor whale shark
behaviour.
For more
information about the work of Dr. Meekan and his
colleagues on the whale sharks at Ningaloo Reef in Western
please visit their website.
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