Swimming with the Sustainable Sharks!

Swimming with sharks

It’s Shark Week!

Amanda Gläser-Bligh
Amanda Gläser-Bligh
Digital Communications and Social Media

During shark week, we only can think about one thing: those cartilaginous, smooth, toothy, biting beings that swim the ocean blue. Sharks have been on this planet for a long, long time - even before the dinosaurs. Their longevity clearly proves that the shark has a good design and that being big, fast & quick with a good attack mechanism is a recipe for survival. And those are the same reasons why the shark is just so terrifying, yet fascinating!

Although humans are not a sought after meal for sharks, surfers can often be confused for tasty seals. And the shark likes to take test-bites before deciding whether or not to continue its attack. That first bite alone can be deadly.

But sharks are also just a part of our ecosystem and can be a barometer for the health of our oceans. And as it turns out, sharks also have a few tricks up their jaws when it comes to saving energy. In turn, there are a few things that we could learn from the sharks - and even a number of ideas that we can borrow from them to act against climate change. With that, here are our 5 sustainable shark facts:

1. Energy Storage with Oil & Water

When we think about energy storage, the talk is mostly about big batteries that can be stored in a garage or a basement, that are often used in combination with solar panels. This can be a great way to store energy at home. But there are literally thousands of ways to save energy in the natural world, and sharks are able to save energy as oil in their livers.

A shark’s liver can comprise up to 25% of its weight, which can help it to store enough oil to go almost a whole year without feeding. This means, the shark can swim on long migrations without having to worry about sources of food in between. Additionally, these large reserves of oils can help the shark to stay buoyant, as they don’t have swim bladders like fish do. The oil in their livers never actually runs out. When it’s time to refill, the shark must feed again.

Talk about efficiency - not only does oil storage keep the shark going, it also keeps them afloat!

2. Sideways Swimming & the Geometry of Diving

Sharks use their fins to navigate the water, helping them to move in whatever direction they want to go. But at least in the case of the hammerhead shark, scientists have also witnessed them swimming at angles for efficiency.

Tracked hammerheads were observed to be swimming at angles between 50° to 75° during 90% of their swim time. Experiments repeated in wind tunnels verified the scientists findings that the sharks were indeed using up to 10% less energy by swimming at an angle.

Sharks are also great divers and there has been a study looking at the ways they conserve energy (whether consciously or intuitively) when diving to hunt for food. It turns out that depending on how deep they want to dive and how far they want to go, they use different angles for descending and ascending. Shark dives take up to four different shape patterns and they always seem to use the best option for their goal. But they sometimes dive extremely deep - to the point that our measuring systems can’t even keep up with the water pressure.

The formula is essentially to use the best angle of dive to resurface and eat with using the least amount of energy. Genius!

3. Design Award

When it comes to saving energy, sharks do it by design. Whether it’s their form, the way they move or their amazing sense of smell, everything that a shark has today is the product of the evolution of a well put together predator.

Their gills can’t actively pump water for more oxygen intake, so they do have to keep swimming to breathe, but otherwise, their senses are highly tuned, including their eyesight. But it’s their skeleton made of cartilage that allows them to turn quickly at high speed and stay flexible.

How is it that something so soft can be so scary?

4. Shark Skin

Sharks aren’t fish, and as such, they don’t have scales. What they do have is denticles. As seen with a microscope, they almost look like roof shingles. But what they perform for the shark is nothing short of a wonder.

It turns out that totally smooth isn’t the best type of surface for smooth swimming. Shark skin is actually very rough, like sandpaper - but only in one direction. The denticles are V-shaped and decrease drag and turbulence, allowing for better swim performance. Designers are today mimicking shark skin when designing swim suits, to also boost human swimmers.

Sideways Swimming
Sideways Swimming

But that’s just the beginning of the uses for faux-shark skin. Coatings in hospitals that prevent germs from settling onto surfaces are incredibly useful. And researchers have created a silicone material, inspired by shark skin, which can be used as a coating for boats to prevent barnacles from settling. And as any boat owner knows, chipping off barnacles is nasty business.

For us, what’s great is that shark-skin materials can be used as vortex generators, which can be applied to wind turbine blades.

5. Sharks as a Climate Barometer

There are over 400 types of sharks in the world, with all kinds of shapes and sizes. So, it’s hard to predict exactly how climate change will affect all sharks. But there are a few things that are likely to happen when the world’s oceans become more acidic and oxygen poor.

Some sharks can be rather large, therefore needing more oxygen. As sharks need to keep swimming to keep an O2 inflow, it will take more energy for them to breath if the oceans become scarce on oxygen resources.

Similarly, acidic water makes it strangely hard for sharks to smell their prey. This will make it more difficult for them to feed and lead to more stress among shark populations.

What’s more, as global water temperatures rise, sharks will be forced out of their current tropical haunts, in search of cooler waters. This means that there could be an overall disruption to the ocean’s ecosystems.

When one or more thing in the oceans get out of balance, we will definitely notice changes in sharks behavior. But no one knows for sure exactly what this will look like.

Jumping the Shark

Before we jump the shark, we’re going to wind this up and say, sharks are more fascinating than we ever imagined and do more with energy efficiency than we even thought possible. While we wouldn’t want to get in the way of a shark, we do admire it’s resourcefulness and hope that we can continue to learn a few new sustainable things from the ocean with continued research.

Until then, we hope that you enjoyed our summary of all this jaws-dropping shark research. Wishing you a very merry Shark Week, indeed!

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