Evan Byrnes

Who I am

I am often asked, ‘What made you interested in sharks?’ but I have never been able to nail down a specific time or event that sparked the obsession. As far back as I can remember, and as all of my childhood family stories go, there was never a time when I was not infatuated with sharks and dreaming of becoming a marine biologist.

However, growing up in landlocked Pennsylvania, USA, I had little contact with sharks outside television and books. I made up for it by roaming local creeks and ponds and keeping home aquaria to get my fill of time with fish. By the age of 13, I had opted to replace my bed with a large saltwater aquarium so that I could watch fish endlessly and learn about how they interact with each other. But this was still not enough to satisfy me and when it was time for college I jumped at the opportunity to pursue my lifelong dream of becoming a marine biologist.

I moved to Florida to attend the University of Miami and it was during an internship in a shark research lab that I found my calling. When I got back from my very first field research trip, I knew I was going to be a researcher for the rest of my life. Not only could I finally spend every waking moment learning about sharks, but I could use what I learnt to help inspire the same passion in others and contribute to conserving shark populations for future generations to appreciate as I do.

From that point on, all my life and job decisions revolved around staying involved with shark research and conservation. One thing led to another and I now find myself lucky enough to be working on my PhD at Murdoch University, Australia, focusing on research using innovative tools to provide insight into how the physiology and behaviours of lemon sharks shape their ecology.

Where I work

Although I am based at Murdoch University, I am conducting my field work in Bimini, The Bahamas, working at the legendary Bimini Biological Field Station (or the ‘Shark Lab’). Bimini is a subtropical island situated at the eastern edge of the Gulf Stream, approximately 90 kilometres (56 miles) from Florida, USA. Surrounded by a variety of marine habitats, including sand flats, sea-grass beds, mangrove-fringed shoreline and deep and shallow reefs, Bimini is home to at least 13 species of elasmobranchs of all shapes and sizes. In 2011, The Bahamas was named a shark sanctuary, giving sharks some much-needed protection from commercial fishing. This protection, along with the rich variety of habitats, allows the shark populations to thrive, providing a unique environment where the biology and ecology of sharks can be studied in a natural state.

The Shark Lab has been conducting research on sharks around Bimini, with a particular focus on lemon sharks, for nearly three decades, and the various projects have provided a wealth of knowledge about many subjects relating to sharks, from reproduction, life history and growth to movement, physiology and even personality and cognition. The abundant information about sharks around Bimini, along with the passionate researchers currently at the field station, provides an unparalleled opportunity to conduct collaborative and multidisciplinary research. I cannot wait to see what new things we may discover about lemon sharks through this work!

What I do

Knowing how much space different animals need to survive is central to conservation planning. When it comes to marine animals such as sharks, however, we have a poor understanding of the factors that determine their home ranges. This is especially true for sharks, where reversing the decline of many species requires spatial management. This project aims to explore how the energetic demands of sharks govern the size of their home ranges, by using accelerometers to study how sharks use energy throughout different habitats. Accelerometers share the same technology used in popular fitness trackers, such as Fitbits, that measure the activity of people; when calibrated, they can determine the energy demand of individual animals –or in this case, sharks. By pairing these ‘fitbits’ for sharks with tags that track their movements, we can tell how and where sharks are using or gaining energy. Additionally, we are combining different dietary analysis and prey surveys to investigate how sharks’ diet and the availability of prey influence their home ranges. Assessing how these factors govern the size of home ranges will help to forecast how environmental change may affect these animals and determine what measures can be taken to improve the design of marine protected areas to better conserve sharks.