Aaron Hay diving with a shark

Star Scientist - Aaron Hay

A Life Aquatic

1 August 2023

Whilst most people would baulk at jumping into an ocean full of sharks, Aaron Hay is the first one in.

This month’s Star Scientist has been fascinated with sharks since he was five years old, but it’s not just the big fish that fascinate him.

Aaron in the Institute's zebrafish facility

Aaron heads up the Institute’s aquarium which is home to thousands of zebrafish and medaka fish and whilst they may be little in size, they have big personalities.

When did your obsession with sharks begin?

My parents would take me to every aquarium whenever they could as a kid. I remember when I was about five, my family was watching the penguins and they turned around and I was gone. Eventually they found me, and I was hanging over an open top tank with a shark swimming around. I was patting the shark's fin every time it went by.

Being around sharks is all I ever wanted to do, so all through school I would pick every science class and I went on to study Animal and Veterinary Bioscience at the University of Sydney.

Aaron with a penguin at SEA LIFE aquarium

Your first career job sounds like a dream. What was it like to work at SEA LIFE Sydney Aquarium (SLSA)?

At that point I just wanted to play with animals and get to learn everything I could about these amazing creatures which are amazing, challenging but also dangerous. It was a huge amount of fun, a job for love not money. The job taught me everything I needed to know about caring for hundreds of species of animals as well as the intricacies of being an aquarist. I did that for five and a half years and then decided it was time for a new challenge.

What made you move on and join the Institute?

I wanted my interaction with animals to have a bigger purpose than purely entertainment. I saw a job advertised at the Institute to work in the aquarium and thought it sounded interesting. I also have a family history of heart disease, with both sides suffering attacks at young ages. I thought it would be great to be able to assist with research that could have not only an impact on my family but countless others too.

When you joined in 2018 the aquarium was almost at capacity – what was it like to join at such a busy time?

We nearly couldn't hold any more fish and at that time we were the largest single room aquarium for zebrafish in Australia which was very exciting. Luckily, at the time we only housed a single species, meaning one diet and one set of environmental conditions. Back then Dr Kazu Kikuchi was still working with us, but he had an opportunity to return to Japan and we had to transport the fish he was studying back to Japan. That was a big operation. We could not move fish, only the embryos so we had to breed 80 or 90 lines of the fish he was studying. It was a huge success, and they were able to create a new colony in their facility.

Which scientists are you working with?

We are working with Professor Diane Fatkin’s team who are trying to learn more about the genetic causes of atrial fibrillation. They are studying zebrafish which are transparent so you can see how the heart responds to changes. We are also working with Associate Professor Emily Wong who is using her Snow Medical Fellowship to study the dark genome. She is using zebrafish and medaka fish to better understand heart tissues. Medaka are a relatively new fish to us and we are only the second facility in Australia to work with these fish which makes it very exciting.

Zebrafish and medaka fish are a world away from the sharks you love. Do you miss working with the big predators?

Zebrafish and medaka fish, like sharks and big fish, have their own personalities. Some are more friendly than others. You have the strong proud fish, the quiet ones, and the fish who are more carefree. We're learning more and more every year about these fish, even down to their social attitudes and the way they swim and interact with each other. They are fascinating fish to be around. My biggest ‘miss’ would be the ability to jump in the tank with the fish and interact with them in their environment.

Aaron with zebrafish

You also look after the Institute’s Xenopus – what are these strange-sounding creatures?

They are a unique type of frog that are purely aquatic and only leave the water to venture into a new watering hole. Unlike other frogs, they cannot extend their tongue, so they use their webbed hands to shovel food into their mouth. They are very fun to watch. We use the oocytes of our frogs to study ion transport and channel physiology. We have also recently started housing frogs for the University of Sydney and the University of Wollongong, so this is an area that is expanding for us right now and we are looking at enhancing our colony size within the year.

You seem to love all animals – but sharks remain your greatest passion. What do you most love about them?

I have always thought of them as the ultimate apex predator. They are intelligent, individual, and intimidating. They are often misunderstood, but their role in our oceans is vital to a healthy ecosystem. I have always supported the fight for them. That and to be able to hand feed them and bond with them is exciting and rewarding.

Do you ever get scared when you are close to a shark?

When I am floating on the water about to descend, there is no panic, just excitement to get below and see what the depths hold.

Aaron feeding a shark

But you are always checking for behaviour. For instance, if a shark is following the boat – stalking it – you are certainly not getting in. Over time you just know when it’s ok. It’s a learned skill and I am extremely comfortable in the water.

Outside of your work, you have been involved in various marine animal rescues. How did that come about?

In my previous job, we handled many rescues for sharks, dugongs, rays, turtles, and lots of different species. Outside of this, I also volunteer for ORRCA, in which I have had the pleasure of picking up injured turtles, rays, and seals, all of which ended up in the back of my car or in the bathtub at home until we could take them into work the following day for treatment and release. Our biggest operations whilst working for SLSA have been working in conjunction with Sea World, National Parks, and ORRCA to twice rescue different dugongs stuck in south coast river systems and transport them back north and release them to their natural habitat. This included an express trip for one dugong from Merimbula to the Gold Coast via RAAF Hercules. We have also rescued a juvenile Great White Shark from Manly Beach, successfully releasing 'Fluffy' back to the wild the following day.

I am really enjoying the best of both worlds right now. I am doing work that has a purpose and outside of work, I get close to sharks whenever I can.

Acknowledgement of Country

The Victor Chang Cardiac Research Institute acknowledges Traditional Owners of Country throughout Australia and recognises the continuing connection to lands, waters and communities. We pay our respect to Aboriginal and Torres Strait Islander cultures; and to Elders past and present.

Victor Chang Cardiac Research Institute - The Home of Heart Research for 30 Years