Johnny Miller
7 min readJun 11, 2018


Documenting Dynamite Blasting in Tanzania

Marine scientist Gill Braulik prepares to dive off the coast of Zanzibar, Tanzania for her Blast Tracker project monitoring dynamite fishing.

Bobbing around on a catamaran near the equator, with just a spit of white sand above the high tide line visible, sounds like a dream vacation to most people. But when you’re working on a highly sensitive operation to map dynamite fishing blasts, the element of relaxation comes and goes like the passing swells of the Indian Ocean.

I’m here as a video journalist to document a team of two marine scientists, who plan to sink acoustic sensors to the bottom of the Zanzibari Channel, in Tanzania. The team is lead by Gill Braulik, a Postdoctoral Researcher at University of St. Andrews, who’s been involved in research and conservation of marine mammals for fifteen years.

“Dolphins!” she calls from the bow, and I scuttle across the heaving deck to see a pod of bottlenose dolphins effortlessly coasting in our bow wake. They’re beautiful, animals in their natural element, and Gill seems more at home with them out here than inside the humid cabin. Jamie Macaulay, a marine scientist from the University of St. Andrews, joins Gill on the deck and we watch the dolphins glide between the split hulls. On the horizon, a rain squall builds in intensity, pushing swells against us in a broadside attack. I can feel the nausea building within me, and remember to note this exact moment, when the beauty and the agony of my body and the surrounding atmosphere coalesced into a perfect, complex whole.

Capturing the hard reality of life as a marine scientist. Photo cred (right): Rahim Hussein

Dynamite fishing is a worldwide phenomenon with regional differences. In Tanzania, a mixture of poverty, abundant fish stocks, and easily accessible explosives means almost guarantees a flourishing illegal blast fishing industry. Gill and Jamie are part of a program which seeks to gather, for the first time, data on where and when these blasts occur. By placing hydrophones in specific locations under the water, they will be able to pinpoint exactly where a blast takes place through a system of triangulation. This will allow data to be collected, maps to be created, and will form a backbone of policy in the region, once complete. The unique part of this project, however, is that the sensors will have no transmitter visible on the surface — a necessary precaution due to the lawless nature of the ocean in this area. Therefore the data will be recorded in an underwater recorder, which has a long-lasting battery pack attached to it and should record any loud noises for a period of about two months — after which time, Gill will need to come back and retrieve them. Supposedly, this is the first use of this kind of setup anywhere in the world.

“Time to get your wetsuit on!” Gill tells me cheerily, and I can hear the excitement in her voice. We’ve already been stymied at several locations — the visibility is bad, owing to the rainy season and the outflow of nearby rivers. The current is stronger than she had anticipated. But even so, this time feels different. We’re in a different location, in the lee of a small island that is almost totally covered at high tide. Supposedly it’s a marine reserve, contains beautiful corals, and is known for good viz. I’m starting to get excited as well.

I wash the dome of my GoPro camera with a soapy mixture of dishwashing liquid, so that the bubbles won’t stick to the Perspex surface, and turn on the Lume cube lights I convinced Code For Africa to purchase. The sun’s rays don’t penetrate very strongly at 22m depth, and water absorbs the red colors of the spectrum…meaning that my footage without the lights will look dark, grainy, and green. I’m happy I have them.

We decide not to anchor the boat, meaning that we’ll have to throw the heavy concrete weights, which weigh down the sensors, overboard at the exact spot we mark with our GPS. The weights are tethered to a floating buoy, which we will then descend to the sea floor. Jamie prepares to toss the weights overboard as the captain inches towards the appropriate location. All eyes are on the sonar as we look for a flat location to drop them on.

“3, 2, 1…OK, drop!” The captain drops his hand and Jamie tosses our weights overboard, the yellow plastic shells descending rapidly into the blue. Excitedly, we note that they are still visible, barely, for almost the entire length of the rope. I thank the Gods of good viz for the opportunity to get clear footage underneath the water.

“OK, now you get ready!” Four of us gear up, SCUBA tanks on, GoPro rolling, and wetsuits zipped standing on the back ledge of the catamaran, as the captain positions us as close as possible to the floating buoy which marks our descent line. “3, 2, 1….OK, go!” We jump into the warm water and immediately I realize that the viz is better than I could have ever hoped — in fact, some of the best viz I’ve ever dived in. It’s at least 20 meters, and the current is almost nil. As we descend, I film from below, and the sun forms a beautiful star just behind the heads of Gill, Jamie, and Hannes (our Divemaster), who are carrying the sensors down between them.

Positioning the sensors on the ocean floor.

The sensors Gill and Jamie have decided upon are water-resistant hydrophones, 3 of them, which are mounted on each corner of a metal triangular frame. The frame needs to be oriented to face north, so that the data is aligned and can be properly placed on a map, and weighted down with concrete. A concern seems to be the prevalence of fishing in the Zanzibari Channel — will the nets snag the recorders? We have decided to place them deep enough (20–25m) and in specific locations designed to mitigate that risk, but there’s no guarantees. The recorder itself is specially made and imported from a New Zealand company, via the University of St Andrews. It’s obviously water resistant, but uniquely, it only records when it hears sound — meaning it can last months, if placed in a relatively quiet location. Passing ships and the sounds of a coral reef may make the memory fill up more quickly. The sensors work in pairs of two, with 6 hydrophones total, which will allow Gill and Jamie to not only orient the direction of the blasts, but accurately map the distance from each recorder — which means, by a process of triangulation, they will be able to exactly pinpoint each blast as well.

We arrive at the sea floor, a sandy flat patch with barrel coral sprouting around us like a stunted underwater forest. Jamie, Hannes, and Gill struggle to move the 20kg weights from their tether over to the sensor, and then tie them with zipties to the actual frame. Even though water makes things more buoyant, I can tell that the work is a struggle, and soon a cloud of sediment hangs in the water like a cloak. I move in closer, glad to have the Lume cube lights, and try to hang as motionless as possible. It’s hard work, to shoot underwater, especially on an active work site. I do my best to avoid them, but I realize trying to remain inconspicuous with a Perspex dome and two bright white lights is probably wishful thinking. The three other divers carry on closing zipties, cutting lines, and orienting the entire structure towards north. It’s hard work and once we come to the surface it will become apparent that all three of the divers have scrapes, bloodied knuckles, and urchin spines embedded into their bodies. The coral itself even burns with a mild sting.

It’s a delicate dance that we all four do, but soon, just as I think I’m getting the hang of maneuvering as a champion underwater filmmaker, they’re done. The three of them float back slightly to look at the sensors, the soft light of the sun illuminating the scene in a perpetual twilight of depth. It’s a strange tableau — a beautiful tropical ocean, slightly modified with a high-tech intervention, and a decidedly global, multifarious issue of overfishing, conservation, and economics. I keep filming and pull back to reveal the scene, which I hope the GoPro captures in all its glory — the unperturbed barrel coral, the distant whine of our catamaran motor, and the sediment gently falling back to the sea floor. While we have two more sensors to sink on this trip, I already feel like I’ve accomplished more underwater than in any of my previous dives, maybe even cumulatively. I can tell the rest of the crew feels the same way. With a slight nod of her head and a crinkling of her eyes to let me know she’s smiling, Gill gives me the “OK” symbol and then the thumbs-up. We slowly rise back to our boat on a flooding tide.

Gill Braulik and Jamie Macaulay are funded by the University of St. Andrews and Code For Africa. Johnny Miller is the Founder of africanDRONE and a Code For Africa News Fellow. Follow more of their work at @Gill.Braulik, @UnequalScenes, and #blasttracker.



Johnny Miller

Photographer. Storyteller. Drone Journalist. Creator of africanDRONE and Unequal Scenes.