ONE ON ONE WITH CHRIS PERKINS
The Shark Bay Research Trust is dedicated to conducting ground-breaking research on the great white sharks and changing the public perception of this incredibly misunderstood species. We caught up with researcher, Chris Perkins who tells us about more about sharks, the research they’re conducting and his passion for the sea.
- Tell us more about your research topic and what inspired it?
The research that we are conducting here at the Shark Bay Research Trust is investigating the potential to use sound as a means to attract white sharks to our boat.
The project is a relatively simple one; it just requires a lot of time on the water to collect the necessary data. We are taking measurements of ambient noise to get an idea of what the underwater soundscape is like, and to see what our sounds have to compete against. We are using 21 sounds in our experiment.
These sounds result from combining different bandwidths ranging from 300 Hz to 1000 Hz with different pulse rates. By the end of the experiment we hope to be able to isolate which sounds white sharks find attractive and to develop a way to incorporate that into the cage diving industry.
- Through your research, why is the method better than using chum which a lot of people are against?
Assuming that this method can attract a comparable number of sharks as what we’re currently seeing with chum, using sound will be quite a bit better than its fishy counterpart, but not for the reason that everyone suspects.
It is a common misconception and accusation that we are feeding the sharks, or even teaching them to associate humans with food, nothing could be farther from the truth. There have been multiple studies assessing this accusation, and they have shown there is no change in the behaviors of the sharks as a result of chumming. In fact, if you compare the chum slicks that are created by the cage diving industry with those created by fish processing plants or some commercial fishing vessels, you’ll find that ours are much smaller. I just wanted to get that out of the way from.
Those misconceptions aside, there are several advantages to using sound instead of chum. Firstly it’s a near instantaneous introduction and removal from the environment. Sound travels at just under 1500 meters/second in salt water. That is much faster than what a chum slick can achieve on even the windiest of conditions.
Another benefit is that sound maintains its directionality in more conditions than chum. As the sound travels away from the speaker it will get progressively quieter. This would make it easy to find the source by simply going in the direction in which the sound gets stronger. A similar principle can be applied to chum; only instead of sound we use smell. The stronger the smell, the closer you are to the source. The problem is that this requires wind and current to draw the smell away from the boat. If there is no wind or current, the chum sits around our boat like a giant puddle. Since there is no gradient in the strength of the smell, the sharks won’t be able to find the boat as easily or stay around the boat for longer. Sound isn’t bound by the strength of the wind to maintain its directionality, making it more desirable than chum.
The use of sound also limits the impact of the cage diving vessels in the area. While the chum slick can extend for quite a ways away from the boat, the perceptible radius of the sound will only be 100 meters. Any louder and you may risk not seeing sharks because the sound is too loud and it hurts the ears of the sharks to get too close to the speaker. Any quieter and the sound won’t go as far and you might not see as many sharks. In a way it is self-regulating and requires that the operator find a balance to achieve the best results.
- What difficulties do you face on a daily basis whilst conducting your research? How do you overcome them?
The biggest difficulty by far is the weather. They call this the Cape of Storms for good reason. In summer it’s not so bad. Strong Easterlies coming off the land are typical, but don’t pose a big threat; it just means a lot of chop on the water. Winter’s another story entirely. We get strong winds right off the ocean then, and when you combine that with a massive swell sometimes you can’t even get out of the harbor. These conditions can go on for days; it’s not unheard of to be shore-bound for a week or more in some of the stronger storms. There’s nothing much that can be done to overcome this. You just have to learn what your boat can handle, and adjust your schedule accordingly.
- What have you learnt during your time at Shark Bay?
Probably the most interesting thing that I’ve learned in my time here is how to better read the sharks’ behaviors. Like all other animals, sharks communicate with other. The big difference is that instead of using sound to communicate they use body posture and body language. Granted I had done my fair share of reading up on this before I came to South Africa, but there’s only so much you can learn without experiencing it first hand. It’s amazing to see how each shark has its own personality and to see how that personality changes (or doesn’t) over time.
It’s also become a lot easier to see when major TV channels (I won’t say who, but they have the word ‘disco’ in their name) try to pass off a curious shark as a vicious, blood thirsty killer trying to break the cage open to get to the diver inside. Or for that matter trying to pass off several sharks as one shark. When you work with these animals for long enough, you learn to use scars, size and even sex to tell different sharks apart.
- What do you aim to achieve through your research?
The main goal of my research is to determine if sound is a viable alternative to chum as a means to attract sharks to a dive vessel. Maybe eventually this could be broadened to work with other species of sharks that are popular with recreational divers. At the moment, though, we’re just focusing on white sharks. If we can demonstrate that sound is a viable alternative to chum we will then focus on incorporating it in the cage diving industry in Gansbaai, starting with Sharklady Adventures’ boat, the Lady T.
- Why is shark conservation and education something you are passionate about?
Ever since I was young I’ve been enamored by the ocean. I knew that wherever I ended up in life, it would always have something to do with the ocean. Even back then, I had a pretty good idea that I would end up in the marine biology field working with sharks eventually. Sharks perform a valuable and indispensible ecosystem service by helping to keep our oceans healthy.
Take white sharks for example. They prey mainly on pinnipeds like seals and sea lions. Pinnipeds consume enormous amounts of fish on a daily basis. This puts them in direct competition for the same resources with many of our fisheries. This, in turn, puts enormous pressure on fish stocks, to the point where some stocks cannot handle pressure by both humans and pinnipeds and ultimately collapse. Now, humans can do their part by developing more sustainable methods for fishing and better fisheries management policies, but in this instance white sharks can help, too, by putting pressure on the pinniped populations to keep them from becoming too large. This decreases the pressure on the fish stocks exerted by the pinnipeds, and leaves more fish in the ocean to support the fish stocks.
That was just one example of the vital role sharks play in our ecosystem. It is difficult to overemphasize their importance, but not many people understand this because we are plagued by movies, television shows, and even some “documentaries” that demonize the shark and portray it as a vicious monster whose sole purpose on this planet is to hunt down unsuspecting beach goers. So, I suppose when you really get to the heart of it, it’s this: I love sharks. And much like when other people can’t stand to see what they love unjustly maligned, so I feel when sharks fall under the malevolent gaze of mainstream media. Therefore, I do what I can to help correct this injustice. Which, for the most part, involves undoing a lot of the damage done by the media.
For more information on the research and more, stay glued to the Shark Bay Research page, http://sharkbayresearch.org/