Shark Week: Four Unique Technologies Saving Sharks from Extinction
The following article mentions the study led by the Institute that demonstrates that scientists can track the origin of shark fins using “zip codes” in their DNA.
August 3, 2011
Jaymi Heimbuch, San Francisco, California
Thanks to humans, as many as one-third of shark species are at risk of extinction and many more species are reaching dangerously low populations. With humans killing upwards of 73 million sharks every year, these important animals need all the help they can get in keeping humans away. Here are four smart technologies that put distance between humans and sharks, helping to keep more sharks alive and healthy.
1. Long-Distance Shark-Measuring Device
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 so that they aren't hassled by us just as we aren't in danger of them. The tool uses video cameras and principles of aerial photography to calculate the length of a body part or total size of a shark within a few millimeters.
2. Shark-Repellent Fishing Hook
As we know, sharks are highly sensitive to electronic fields in the water -- picking up the electronic fields produced by fishes' bodies is how they're able to locate prey. Live Science reports that the SMART Hook, an acronym for Selective Magnetic and Repellent-Treated Hook, will help keep sharks away from the fishing lines intended for other species of fish. The hooks' magnetic and electronic features are intended to make sharks want to stay well away from them, even if there is bait attached.
The SMART hooks have been tested with bonnethead sharks, and the researchers saw success. Of 50 different tests with two groups of sharks, there was a 66% reduction rate of baits taken from small sized SMART hooks (which would be used for recreational fishing) and a 94% reduction rate of baits taken from large sized hooks that would be used in commercial fishing.
3. Tracking Shark Fins with "DNA Zipcodes"
Part of the reason enforcing restrictions and bans on shark finning is so difficult is that it is nearly impossible to trace where shark fins landing in stores and restaurants came from. Without knowing the source, it's hard to put the smack down on illegal finning. However, that might change with a new method for using the "zip code" found in shark DNA, which helps researchers know exactly what part of the coastline a fin came from.
A team of scientists led by Stony Brook University's Institute for Ocean Conservation Science has figured out that dusky sharks and copper sharks -- both heavily hunted for their fins, with the dusky shark species classified as threatened by the IUCN -- have distinct populations living along different areas of coastlines. By looking closely at the "zip code" embedded in the DNA of the fin, the researchers can pinpoint from which population that shark came, and therefore get a step closer to finding out who is exploiting the species. This strategy can be expanded to other shark species with similarly distinct populations -- and that can go a long way in pointing out where laws against shark fishing need to be enacted or better enforced.
4. Electronic Shark Shield for Swimmers
A few weeks ago, swimmer Penny Palfrey completed a record-setting swim but the news was tainted with reports that at least one member of her crew killed three Oceanic whitetips (a threatened species) during the swim. Competitive swimmer Diana Nyad doesn't want to have the same issues and is using Shark Shields during her upcoming summer swim from Cuba to the Florida Keys.
According to the New York Times, Shark Shield sends a 3D electrical wave that affects the Ampullae of Lorenzini, the part of the shark that can receive and decode electrical signals which helps them, among other things, locate prey. The pulses can be felt by sharks from as far as 30 feet away. While they may come closer to investigate, the Shark Shield's pulses become increasingly uncomfortable to the point that it can even cause muscle spasms at a distance of about 12 feet which, in theory, will send sharks swimming the other way.
Using strategies like this will help keep both sharks and people a safe distance from each other, and keep both alive and healthy.
News release about the study
Article on Tree Hugger.com