by Jaymi Heimbuch, San Francisco, California
Science & Technology

Photos ©SaveOurSeasFoundation / PeterVerhoog

Size matters. When it comes to understanding the health of an animal, that is. Researchers have come up with a smart new way to measure the size of sharks while maintaining a safe distance from the predators.
Normally, sharks are measured with either guesstimates based on the distance between their dorsal and tail fins, or via catch, measure, and release. Often that means getting a little too close for comfort — both for the diver’s comfort and that of the sharks. But knowing body size is a key component of understanding just how healthy a population of sharks is since the bigger (and therefore older and more well-fed) the better.
The Save Our Seas Foundation in conjunction with Dr. Mark Meekhan of Australian Institute of Marine Science and Gabriel Vianna of the University of Western Australia has created a new tool that measures sharks with great accuracy while maintaining a reasonable distance from them. The tool seems like a boon more for the sharks than the divers. Sharks usually aren’t a threat to divers, though getting too close without being aware of how to move around a wild animal can lead to a bad situation. But really, this tool allows researchers to get the information they need while giving the sharks plenty of room to swim hassle-free.

According to Save Our Seas, “This is done using a stereo-camera system operated by a diver (diver-operated video or “DOV”)… Paired video cameras in housings film the sharks and a diode (light) in the front of the cameras allows the researchers to synchronize frames of the video. Using principals originally developed for aerial photography, these researchers are then able to calculate the length of any body part and total size of the animal with a precision of a few millimeters.”
Keeping within a few millimeters is impressive! What is possibly even more exciting is that by measuring the same sharks year after year, researchers can keep tabs on growth rates as well as keep a documentary of sorts of the animals within a population which can be used for other research later on.
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(Source: www.treehugger.com )