This week is Shark Week: an annual celebration of these charismatic swimmers whose numbers have dropped dramatically owing to human activity. So how can we better share the ocean? Georgia Mills has been investigating our relationship with these fearsome fish...
Georgia - We are obsessed with having sharks on our screens. There's mega shark versus giant octopus, a film called Sharknado and, obviously, Jaws. And this week is actually known as Shark Week in American with a whole channel devoting their output to shark documentaries but off the screen in real life our relationship with these fish is less than perfect. Shark attacks can stir up tremendous fear and shark numbers are dwindling due to human activity. To find out more about how our relationship could maybe improve, I went to meet Jamie Oliver, Senior Curator at Sea Life London Aquarium and also got to see some of these fish face to face...
Jamie - So we have several species of shark. We've got this one coming towards us now called a Brown shark, also known as a Sandbar shark. You can see it's got a real classic shark shape - a nice large dorsal fin. And just behind it there we've got a Sand Tiger shark...
Georgia - Oh he's a big fellow, isn't he?
Jamie - He is. He's one of our biggest sharks at around 10 feet long - really beautiful animal actually. Actually quite harmless but they have this sort of fierce look about them because they're always bearing their teeth, you can always see their teeth. A lot of sharks hide their teeth, you can't see them when they're swimming around but the Sand Tiger's always got their teeth on show and it looks pretty awesome.
Georgia - Awesome indeed! But also very noisy so we nipped behind the scenes where I asked Jamie why sharks had such a fearsome reputation?
Jamie - There is a certain amount of misunderstanding when it comes to sharks. They're not really these dangerous predators, certainly towards humans, that we think they are. And the media do like to shout about it whenever there's a shark bite or a shark injury because it can be quite intensive in terms of injury. However, for the most part, they need our respect, they need our care, our love because they're really endangered in many parts of the world.
Georgia - Shark attacks may be extremely rare (there is only about 70 a year), but there's still pressure to cull them in popular surfing spots like Australia. But perhaps there's a way to make sure people and sharks can share the oceans. Professor Shaun Collin at the University of Western Australia has teamed up with Shark Mitigation Systems, and they're using their knowledge of shark biology to design a range of so-called shark proof wetsuits. I went to visit Shaun to have a look at some of these designs, the first of which was a funky blue and teal pattern, and asked him about how they're going about designing these wetsuits?
Shaun - So our approach was to look at the visual system. Firstly whether sharks can see in colour and, unlike most vertebrates, sharks don't see in colour, they're in fact colour blind. So contrast is actually more important to them in finding prey than colour is. So we used that information and, actually, took a lot of light measurements within the water off the coast of W.A. and tried to work towards a way of camouflaging the silhouette, or the high contrast boundary produced by a human in the water, which generally would be dressed in say a black wetsuit, for instance, which is the predominant neoprene colour.
So with reflectance measurements of different materials and different colours, and knowledge about the light environment that the animals live in, we were able to model and construct the optimal camouflage pattern that could be put onto a wetsuit to camouflage the wearer at different depths. Whether it be near the surface, halfway down or even at quite deep depths so thereby potentially helping surfers versus divers which would go deeper, so that's two of the designs you can see here. These are camouflaged wetsuits of slightly bluey-green tinges but, of course, this would be seen as shades of grey by the shark, not the colour that we in fact see them.
Georgia - If these two wetsuits works on camouflage, there's one on the end there that's got these white stripes across a very dark blue background. This doesn't look very camouflaging to me. Does this work in a different way?
Shaun - It certainly does, yes. The other design is quite the opposite, it's actually a very high contrast presentation where it's black or blue with intermittent stripes of high contrast and low contrast. And yes this will, in fact, make the wearer more obvious to a shark and will, hopefully, elicit the same behaviour but for a different reason. The different reason being that most sharks do not like striped patterns, as in they see striped patterns as being a deterrent, and indicator of something venomous. Normally animals avoid such patterns in nature and there's lots of examples of how that works with sea snakes and various other animals that are also striped. We have this conspicuous pattern that we've looked at and the banding periodicity, if you like, is governed again by our research on the visual acuity of sharks, so we've actually assessed what their spatial resolving power is. The patterns are actually designed to be obvious at a certain distance to a range of different predatory sharks.
Georgia - Well they haven't been able to tests these wetsuits on human subjects. There are obviously some ethical issues there. Shaun and his team have been using barrels instead and, hopefully, it won't be too long before they have some results out. So, if you're a surfer, watch this space. And, if science can help us to avoid shark attacks, can it also help us to conserve them? Because despite being more ancient than the dinosaurs, many species of shark are in real danger of extinction. Back to Jamie at Sea Life...
Jamie - One of the big factors is overfishing for their fins. There's a lot of sharks taken out with estimates between 20 and 70 million sharks per year taken from the sea. That's just not sustainable for a species that's slow to reproduce and that's having a devastating effect and, for many of those sharks, all that's used is the actual fin in shark fin soup, which is a tasteless broth really that has no real need for the shark fin anyway. There's artificial versions out there now but it continues to be a very popular dish in certain parts of the world.
Georgia - So what kind of things are being done to try and protect sharks?
Jamie - Many things. Certain governments are trying to create marine protected areas where fishing is banned. Here we're trying to educate all of our guests that come through the door and inspire them to go away and campaign, and sign petitions, and get out there and really shout about these creature, and really care for them.
Georgia - And just don't order the shark fin soup?
Jamie - Absolutely!. Don't go anywhere near it!