When I was a child, I wanted to be marine mammal veterinarian. My mother told me there was no such thing. It’s funny how the world turns, as life somehow brought me from Canada to Australia six years ago, and since then I have not only become an an Australian citizen, but have also become a PADI (Professional Association of Diving Instructors) Scuba Diving Instructor that teaches the specialty Shark Conservation. So, what’s the catch you might ask?
Well my interest in sharks came from spending time with them underwater for my first time. This was in Sydney, shortly after I moved to Australia, while scuba diving with the endangered Grey Nurse shark in Maroubra. They looked so scary with their pointed teeth, all the while they were more scared of our loud bubbles and scuba diving gear. As a veterinarian, it is my role to speak up for animals and look after their welfare. When I learned how misrepresented sharks were, how awful humans are treating them, and how important they are to our environment, this is where my credentials and ongoing dedication to sharks step in.
Through my career as a veterinarian over the past fourteen years, science and medicine have proved the importance of healthy ecosystem relationships towards the health of individuals involved. Being a scuba diving instructor has allowed for constant observation of biological communities in the ocean and their connection to life on earth. When we discuss sharks in relation to attacks on humans, it is important to remember that humans have not evolved in the ocean, nor have sharks ever been reliant on humans for food. As sentient beings, humans naturally react emotionally seeking revenge and solutions in response to traumatic events that threaten us. But this attitude is perpetuating a realistic plight against the ocean, and specifically sharks; at the expense of evolution and science. With shark numbers rapidly decreasing, it is time to ask ourselves, what will our future look like if we selectively remove the ocean's apex predators?
Sharks have existed in our oceans for over 400 million years. As apex predators they dominate the food chain and adapt to its availability. Scavengers of the sea, sharks change their dietary preferences in response to food availability after populations of one food source become scarce. They have unique anatomical adaptations such as electrochemical receptors called Ampullae of Lorenzini around their snout, which detect vibrations in the water associated with dying fish, aiding their ability to hunt. This becomes important when we look at the olfactory and sensory cues that sharks use when selecting prey. Sharks balance marine ecosystems by managing species populations and removing sick individuals from healthy populations.
Sharks are also very curious. On a cage-diving expedition to Port Lincoln in South Australia, my immediate response to watching Great White Sharks hunt was to compare them to the domestic companion carnivore many of us keep as pets; the cat. Like a mischievous cat hunting a mouse, the sharks circled and stalked burley (tuna blood and guts) on the surface, using speed and agility to engulf it. Other cage-diving operators which didn’t have a licence to use burley instead played music, including ACDC’s classic rock, using sound wave frequencies to attract them. Understanding the biological adaptations of any species further enables us to predict their behaviour. We know that Great White Sharks eat seals. Having swam with Australian Sea Lions myself, it became obvious that these playful souls enjoy the thrill of rolling through the water when feeding. It shouldn’t be surprising then that when humans choose to play in the ocean and dangle from surfboards, their splashes and movements might send inviting cues, similar to what nature intended. Coupled with inherent curiosity, we have learned to predict this as natural shark behaviour. They are not predators of humans.
So, why are humans so afraid of sharks? Contrary to popular belief, the Australian Shark Attack File in 2015 revealed that shark-attack injuries and fatalities total very low in the larger scheme of injuries/deaths related to other water-related activities. In fact, more people die of falling coconuts each year than shark attacks. Yet for many, simply saying the word “shark” evokes a reaction of fear. As a scuba diving instructor, when asked what prevents participants from learning to dive, many mention that same word, sharks. Unfortunately, societal views and the media, as was conveyed through the 1975 Hollywood film JAWS, portray Great White Sharks (in particular) as ravenous man-eating beasts, instead of the apex regulator of the ocean’s food chain that they are.
I argue that rather us fear sharks, sharks should fear us. With few natural predators, threats to all sharks include human profit-driven industries including shark finning (for shark fin soup and natural remedies), shark meat (in Australia labelled as flake), coastal development (claiming shark nurseries), pollution, and poor fisheries management practices, which render sharks as by-catch. And it doesn’t stop there. Political action in response to reported shark sightings now threaten our ocean. Australia is currently placing targeted, baited drum-lines to kill sharks in waters where sightings or attacks have been reported. Not only does this promote a false sense of security for those of us that choose to swim in the ocean (there will still be sharks, as well other stinging/biting organisms); for sharks, it is accelerating their plight. Some shark species take up to twenty years to reach sexual maturity and reproduce, so considering this, killing one reproductively mature female could preclude generations ahead. And like in any ecosystem, when we remove one key species from the food chain, overpopulation of those dependent on the species for ecological balance often results.
Like sharks, we depend on the ocean for life. Containing 97% of earth’s water, the ocean produces more than half of the atmosphere’s oxygen and is a major absorber of greenhouse gases, specifically carbon dioxide. Ocean waters connect to water on land, and circulate through the atmosphere by the hydrologic cycle. In essence, it is a necessity for all. We take risks when we drive a car, and we risk injury by sharks when we surf or swim in the ocean. On land and in sea, for any ecosystem to sustain healthy populations, it must achieve balance. My sincere sympathy goes out to any injured victims of shark attacks. We must realize however that baiting drum-lines and killing random sharks will not guarantee that shark encounters are not possible. In fact, it selectively targets the apex predators of the sea, which regulate lower levels of the food chain, those that we rely on for sustenance. In essence, the only future jeopardized by this practice, could be our own.
Learning more about sharks, and even learning to scuba dive to witness their natural behaviours and complacency underwater can be a great way to witness them up close and personal, and realise yourself how over-represented they are as “monsters of the sea.” I always look forward to teaching people about Shark Conservation and scuba diving with sharks. Please reach out and take a course if you think your shark-myths need dispelling!
Dr. Erika Sullivan
PADI Staff Instructor, Shark Conservation Instructor and Veterinarian for Vets4Pets