Character Interview: Paul von Blerk (KZNSB)

Character Interview: Paul von Blerk (KZNSB)

Posted by Esther Jacobs Overbeeke on July 6, 2016

Interview with Paul von Blerk, Project Specialist, Kwazulu-Natal Sharks Board

Mossel Bay, April 2016:  Paul von Blerk specializes in electronic shark repellents with the Kwazulu-Natal Sharks Board Maritime Centre of Excellence. He’s worked with the Shark’s Board for 34 years, and for the last couple of decades, he’s dedicated his life to creating and testing an alternative, eco-friendly system that keeps both bathers and sharks safe. Throughout April, Oceans Research assisted Paul in testing an electronic device on our Mossel Bay white sharks, with incredible results.


Can you give a brief overview of your shark deterrent?

In the very late eighties / early nineties, our previous CEO, Graham Charter, hit on the idea of trying to repel sharks by means of utilizing electricity in the water. It grew from an in-house little experiment, getting bigger and bigger and we started hiring experts. It culminated in 2014/2015 with the experiment in Glencairn. A full-scale deterrent device was deployed there and activated for almost seven months. Sadly, no white sharks pitched up. What we’re trying to achieve is to deter sharks from their natural movement into bathing areas by use of electricity. It sounds horrific and scary, but actually the electricity we’re putting into the water is not what we get out of the wall plugs. It’s far reduced and we know that sharks have this extra sensory system so they’re more sensitive than us when it comes to electricity. An analogy I use when explaining this to people: sitting in front of a fire, if you get too close and uncomfortable, you move away. So that’s what it is for the sharks, they can swim towards it and then decide for itself to move away when it gets too uncomfortable. What we’ve seen to date here in Mossel Bay has been very exciting. Thanks to Oceans Research, your crew, your boat, your equipment etc, who we couldn’t have conducted this experiment without, we managed to test a small version of the device. The animals did engage with the device, which, as a smaller version gives off a smaller range than a full-scale device like the one deployed at Glencairn. All the reactions we saw from the sharks was very positive. We’re very confident that we can move to the next step. All the wishes we have had for the last 20 years have culminated in Mossel Bay. It’s really very rewarding to see this and I’m very confident that this device can be utilized as an environmentally friendly way of dealing with shark interactions with humans, compared to what we currently use.

What is this difference between this kind of device and others currently available?

Shark Shield, a product that’s offered just now, is actually Shark’s Board technology. It was originally known as The Pod. When we started in those days, we could have worked on a personal unit or we could have looked at an area barrier. We decided to start with a personal unit as we thought it would be easier. That progressed from the Pod when we went into partnership with the Australians, who currently market it as Shark Shield and it’s used around the world.  The way a pulse is delivered into the water is the unique thing about it. What we have done with the area barrier, this big-scale device, is kept the signal the same, but increased the power slightly. The power density of the delivered signal has gone up because of the way it’s been deployed over greater distances. It’s a very simple electronic pulse in the water. I know people think electricity in water is scary. Yes, it is dangerous, but it is very difficult to make electricity travel far in water. To attenuate the signal is very difficult and this is where we think we have the upper hand with this. The other devices on the market have a much reduced signal and sometimes their frequencies are different, in most cases they are, and the power is far less. Sharks Board have gone to great lengths and huge expense to test this over the years. We’ve also had the independent testing of our technology. Charlie Huvenier has come out here to test the technology. I’m sure more people also will as we move forward in testing and further development of this technology. A lot of the other shark repellent products in the market cannot support their claims due to lack of product testing and when asked for test data, they cannot produce the required data.

What was the difference between testing the device with white sharks in Glencairn, and Mossel Bay?

In Glencairn they’re extinct *laughter*. No, let me explain. Mossel Bay is the ideal test sight. Ideal conditions and an abundance of white sharks here at this time of year. That’s the comparison with Glencairn where we didn’t record one white shark sighting even though we had cameras filming the site from sunrise to sunset every day for seven months. All we got there were four copper sharks, a couple of skates and rays, plus dolphins and seals. Here we got to work with white sharks from the first day. 2014/2015 was just a very slow year for white shark activity down in the Glencairn area.

How quickly could these replace shark nets and drumlines?

Let’s be realistic. The nets that are in Kwazulu-Natal not only catch white sharks, but other species of sharks. We haven’t tested this technology on sharks such as tiger sharks and bull sharks that are in the three top species we worry about. What I personally would like to see is a full-scale device being implemented and monitored for a year or two in an area known for sharks, and then decisions can be made. The decision doesn’t lie with us as we’re a government department, so the decision would lie with the government to move the project forward. If we could go all in with the technology, products made to specifications, full-up engineering etc on a beach like Dias in Mossel Bay, I think we could do it in 18 to 24 months from a commercial perspective. I’m confident that the correct decision will be made by our CEO in this regard and we would all like to see it happen as quickly as possible.

So in terms of bull sharks and tiger sharks, will you be looking to do testing similar to the testing conducted in Mossel Bay, but in an area known for these sharks?

We’re currently looking at areas to carry out this testing and have a couple in mind. What people have to understand is that what we’ve tested here is specifically for white sharks. We know that it can repel other sharks, but we need to validate that through testing. What we’ve got now might not be the ultimate device, but we will continuously look to further it and improve it. That would be something that is ongoing.

Well it’s certainly moving in the right direction from what we’ve seen. Would a big demand or not much demand for the device make a difference in terms of applying it to other areas?

The Kwa-Zulu Natal Sharks Board has a mandate to only work in the Kwa-Zulu Natal region. If another province approached us about getting the device, and it was up and running already, then we would say it is an option. The demand will always come down to finances. Environmentalists will be all for the device, but financiers might not be. If you look at areas such as Western Australia where they’ve deployed an eco-barrier, some people are for it and some are against it. We need to be realistic. If there’s a shark incident suddenly everyone is all for the device, but then a year later everyone has forgotten about it.

Is the system easy to duplicate for roll out if there is a big demand for it?

We now have a data pack that’s been created by Institute of Maritime Technology (IMT) with our technology’s specifications. We can take this data pack anywhere in the world and have the system replicated. I’m convinced that if we have the budget available, we can create and implement a system in 18 to 24 months.

Will it be a permanent structure or is it removable?

There are two ways we can use this technology. At Glencairn it was a permanent structure for a robust environment. With Mossel Bay we wanted to use a smaller device that could be removed at the end of each day. I see two types of systems being offered… one being permanent, and one that would be deployed e.g. one to two days a week etc.

Can the permanent one withstand rough seas?

Yes it can. The difficulty we face is that you can put something in the sea and that’s achievable, but put something in the surf zone and that’s where the trouble comes in. That’s where we have to look at overcoming it either by designating rocky point structures or looking at fixed points at different locations as and where it may be needed and deployed. I am confident that we can overcome these limitations.  At the end of the day we will be looking at a choice for surfers… some beaches will have this technology and others won’t.

Other than repelling sharks, do you have any personal measurement of the project’s success?

We’ve had a lot of interest from companies and also from people who want to get involved and bring their ideas to the table.

If businesses are approaching you that’s a sign they think there will be a demand for it.

I hope so.

Have there been any surprises during trials?

It’s been a very trying month for us here in Mossel Bay. The equipment failed us a couple of times in terms of the signal output. I’ve always been very confident about this technology, but admittedly I was very surprised to see the number of sharks in Mossel Bay that we had to test the device on. I am very grateful for it though. It’s been over 20 years and we have known that this technology can do the job but we haven’t been able to demonstrate it up until now. When we analyse the data, it will clearly show you that when the device is activated, there is marked avoidance from the sharks and they stay away. We had equipment breakdowns, not technology issues so that took a lot of running around and perseverance to fix, but if you’re going to do something, you have to give it your best.

If we talk about shark conservation, would you say this project has been an achievement, or how would you measure it? I know it’s a touchy subject.

The Shark’s Board have a mandate from the government to look at any other research that would benefit both humans and the animals involved. So this is something we’ve been driving. We’ve looked at drum lines and dolphin pingers, but this technology is something that we’ve clung onto and persevered with. I’d like to think that after all this effort that’s gone into it, there will be merit in it and it will definitely contribute towards the environment.

So, you get to a stage where the system has successfully been rolled out worldwide… what’s next for you?

I’ve been on this project for a long time and people have come and gone, but there’s been a huge team involved in this. Everyone in the Sharks Board that’s been involved is going to have a feeling of personal satisfaction. Our CEO Mthoko Radebe needs to be thanked for his trust in the team and for driving this project to where we are today, Graham Charter has been integral in this project. Jeremy Cliff was an absolute rock throughout as was Mark Anderson Reed from an operation point of view. All the field staff that have assisted me over the years, our South African Space Agency and all the professors and scientists from there, The Institute for Maritime Technonology (IMT) and their passion for the project and critical input, everyone that’s been involved in this project hasn’t seen it as work as yet. It’s been a challenge to them.  So when everyone sees the results there will be smiles all round. Oceans Research can smile too as they played an important part in it. I would certainly love to see this rolled out and utilized, even if it’s just on a small scale. When that day comes we can sit back with a beer and smile and ask what’s next?

Will you be back in Mossel Bay?

Absolutely. You have everything here. For white sharks, even though I’ve spent a lot of time in Gansbaai, there’s no comparison.


Paul and the Oceans Research field specialists and interns watched 52 great white sharks approach the pulsing cable in the four-week trial, which finished with a 100 per cent success rate in repelling sharks.

For information on Oceans Research and their internship opportunities visit:

Keen to learn more? Join us on Facebook