Alison Towner

Who I am

I grew up in Lancashire, England, where the weather is mostly wet and it’s a long drive to the coast. Most kids of my age in the 1980s were playing with Action Man or Barbie, but nothing fascinated me more than sharks. My proudest childhood possessions were my shark videos, the typewriter on which I created shark fact sheets, and my ceiling-high collection of shark books. I was an official shark nerd and proud of it, spending hours engrossed in the adventures of Jacques-Yves Cousteau and Australian shark experts Ron and Valerie Taylor.
I’m pretty sure that my passion for marine life comes from my late father; we parted ways when I was five years old. Being a journalist and an angler, my dad wrote a novel about salmon and their epic migrations, which I read at the age of 11. I immediately realised that my fascination for ocean life was no coincidence; in fact, it still keeps the two of us connected somehow. I vividly remember the first time I watched real (non-Spielberg) underwater footage of a white shark; this had to be the most magnificent creature on the planet. From that moment I knew that, no matter what, I had to work in the ocean and study sharks.
At the age of 20 I graduated from the University of Wales with an honours degree in marine biology and went to work on a Greek island and then in the Red Sea as a scuba-diving instructor. I was subsequently offered the position of marine biologist for the Dyer Island Conservation Trust in Gansbaai, South Africa. I have been incredibly fortunate on my path so far, and have been able to write my MSc thesis on white sharks in Gansbaai through the University of Cape Town and Marine Dynamics Shark Tours.
There are still many questions about white sharks in this area that I’m endeavouring to find answers to, and I believe that being based here in the field year-round presents the perfect platform to achieve this. The role of a young scientist involves constantly learning, adapting and asking more questions. I look forward to the challenge as I embark on the adventure of a PhD project on white sharks here. I reckon Dad’s proud too.

Where I work

Gansbaai is simply special. In terms of white shark sightings, nowhere else compares to this truly privileged area – not to mention the fact sharks may be encountered year-round. I liken the site to a pit stop, with the shark as a Formula One racing car travelling the entire South African coastline on its annual journey.
Providing the perfect refuelling station for a white shark of either sex or any age, Gansbaai is protected only on its western side, by Danger Point, and is known for its variable, wind-driven sea conditions, which play a role in the bay’s high levels of marine productivity. Inshore is a 4.5-kilometre stretch of pristine sandy beach and parallel to this runs a large expanse of shallow reef. A multitude of fish prey species aggregate here, ideal food for juvenile and sub-adult white sharks.
One of my favourite times of year is November, when I can take a boat into the very shallow water close to the beach and observe sharks basking in the surf – I have counted more than 20 in one morning. They seem to be resting in the warmer oxygenated water, perhaps to aid digestion.
Four kilometres due south lies Dyer Island, a nature reserve where various seabird species breed. Geyser Rock, home to a resident population of Cape fur seals, lies next to Dyer Island and separating the two is a shallow channel known as Shark Alley. In winter, between May and September, white sharks patrol the alley’s crystal-clear waters right alongside the seal colony. I have acoustically tracked large males that swim back and forth and opportunistically grab a seal from the colony’s edge.
We have observed white sharks feeding on seals, reef fish, skates, rays, smaller sharks and dolphins around Gansbaai. The area is an incredibly rich biodiversity hotspot and fully deserves the title ‘white shark capital of the world’.

What I do

Ultimately my project aims to understand whether the white sharks’ long-term movements are driven by cage-diving activities, by environmental conditions or by prey in the Gansbaai region. The results from my Masters identified that environmental conditions are an influence on the sex and numbers of sharks in the bay. Shark cage diving operations (SCDOs), however, probably impact Gansbaai more than any other area in the world. As tourist numbers to South Africa have increased, so too has the popularity of white shark cage diving. The arguments for and against the industry are highly emotive and this research topic needs a balanced and critical approach.
White shark movements can be monitored in detail, by manually following the shark for short periods using active acoustic tracking, as well as over longer distances and periods. Evidence from other white shark aggregation sites suggests that SCDOs do not influence shark movements over short times and distances, but less is known about longer time frames. At present we do not fully understand shark behaviour towards SCDOs, nor how SCDOs affect the length of time white sharks stay in Gansbaai.
Through the active tracking dataset I have been collecting since 2010 I hope to provide a baseline insight into how individual sharks of different sizes and sex respond to SCDOs. Active tracking – physically following a white shark around the bay in a boat with a hydrophone – is logistically challenging, however, and at the mercy of variable weather conditions. We therefore use it in combination with passive monitoring in the form of long-term acoustic tags that enable us to track individual white sharks over a number of years, provided they pass listening stations (moored receivers that can detect the tag’s radio signal). Satellite tagging will also give us insight into where sharks go on their long migrations when they leave Gansbaai. Once we have a better understanding of how SCDOs affect white sharks in the long term, we will be in a position to discuss the future of the industry if expansion continues.
Save Our Seas Foundation provided the first set of listening stations for the Gansbaai area, as part of a national network array. The combination of tagging methods will provide information suitable to start testing hypotheses for this study.