Ocean as a Lab: Shark Finning



My name is Mahmood Shivji. I'm the Director of the Guy Harvey Research Institute, and I study shark biology and shark conservation. What we have here are fins from over 400 sharks that were confiscated by NOAA's Office for Law Enforcement agents from a commercial fish dealer. And what they've done is they've asked us to see if we can identify these fins using our DNA techniques, because they want to know whether some of these fins come from species that are illegal to catch.

These are the large fins that are used for steering primarily by the shark. They're used to make a delicacy that's known as shark fin soup. These fins are typically exported to Hong Kong and sometimes to mainland China. The demand for shark fin is so high, sharks have been overfished worldwide. In fact, some of our studies have shown that up to 73 million sharks a year are being killed, just to supply the demands of the shark fin trade. And if you kill all the sharks off, then the entire ocean ecosystem suffers.

I'm gonna take this tiny piece of fin and extract it's DNA. What I need to do is put this DNA into this machine here. It's called a Thermal Cycler. This machine will allow me to make over a million copies of the DNA, which will then make it easy for me visualize a DNA fingerprint. The DNA fingerprint simply represents unique sequences of DNA for every individual shark species.

So what we have here, is the DNA that's been copied. And now, to visualize this DNA, I'm going to have to add a dye to this, so that the dye can be easily seen by the eye. And then apply an electric current, and the DNA is now actually going to move towards the red pole and generate a DNA fingerprint that will be easily visualized, so then I can identify what shark the fin came from. You know what's really cool about this is that we've discovered a technique here, that is actually being used in practical applications in law enforcement. We've developed these forensic markers to identify 30 shark species that are found in fin trade.

So these bright bands represent the DNA fingerprints of those fins that we tested. But now, here is the key. The band you see over here is actually from a dusky shark. And dusky sharks are protected, and therefore illegal to catch.

The next step is that I will write an affidavit for the NOAA's Office for Law Enforcement, and the lawyers will actually build a case against the individual from whom they confiscated those fins. And so we are providing the teeth to law enforcement. And this then acts as a deterrent for people from catching illegal species. Someone might ask, "What's the point of conserving sharks?" Sharks are what we call top-level predators in the oceans. They are a major player in maintaining the health of the entire marine ecosystem. If the shark populations are really decimated and they're unable to recover, that can affect the health of our entire ocean ecosystems, and then therefore also our own health.