Counting fish is key to ensure sustainable fish stocks and food security across the world. But you can’t ask them to line up can you? So how on earth do you count fish? To assess population size of fish in the Australian waters - the third largest marine domain in the world - scientists take genetic samples of juvenile and adult fish species and test them. This way they can see if there are parent-child relationships, track where fish are born and where they lived. When there is a good sample size the fish population can be determined. It seems so simple… But imagine scientist Tony at sea. The waves are high and the boat is rocking back and forth. He almost loses his balance once he hooks a fish whopper. Then comes the tricky part: cutting a sample of the slippery, frolicking fish. When he finally succeeds, he releases the fish and tries to put the sample in a labeled tube. When Tony is about to throw out his rod again, the waves are splashing over the edges of the boat. Tony trips and accidentally knocks over the box with samples. The tubes lie on the bottom of the boat floating in seawater. Tony tries to save the samples, but most of the identifying stickers on the tubes are soaked through the water. Half of today’s work is down the drain and unfortunately not for the first time. Desperately seeking for a solution, they ended up with BIOplastics in Landgraaf where they master the technology to laser mark each individual tube. Every tube has an attached cap with a laser marked, unique and non-erasable code. No more sample loss and opening and closure of the tubes can be done with one slippery hand only. “It’s without any doubt, the only plastic we can’t do without”, says Tony. So next time when you prepare a tuna steak, remember how this particular piece of plastic pays a big role to ensure there is enough fish on your plate.