Illustration Stijn Schreven A botched experiment, a rejected paper: such things are soon labelled as failures in academia. As for talking about them — not the done thing! But that is just what WUR scientists do in this column. Because failure has its uses. This time, we hear from Hendrik du Toit, a PhD researcher in Experimental Zoology.
‘For my PhD research, I study the swimming performance of flatfish like sole and plaice, among other things. There is standard equipment for this: the swim tunnel. You place a fish in a small chamber through which water flows. The stronger the flow, the harder it has to swim. I had already worked with such equipment during my Master’s thesis, so I was full of confidence.
‘I filled the swim tunnel with water at 10 degrees Celsius (like the North Sea), carefully lowered a fish into the water, attached the lid and camera, and switched on the flow. Instead of swimming, the fish sank passively to the bottom, drifted with the current, flipped over, and landed with its back against the mesh of the chamber.’
I am now in the third year of my research and I finally have a working version
‘Strange, I thought. When I repeated the experiment with other flatfish, the exact same thing happened. That’s when I started to get frustrated. I thought: why aren’t my fish swimming? In hindsight, I should have seen it coming. In nature, flatfish bury themselves in sand and prefer to stay still. They only swim when they have to.
‘One of the great things about the Experimental Zoology group is that many colleagues have a technical background and are bursting with creative ideas for equipment and methods. That helped me not get too attached to a single design. I delved into the literature and built at least five adjustments to the tunnel myself, each with modifications to encourage the fish to swim.
I am now in the third year of my research and I finally have a working version: one with an inclined plane with a special grid that prevents turbulence and creates an upward flow that encourages the fish to swim. I will analyse the results soon.’
