The surprising science of prawns and pipes

Global demand for prawns has been rising exponentially since the late 1990s. There is, however, an ecological limit to the number of ocean-caught prawns. The solution? Farmed prawns.

Dr Ha Truong from CSIRO was one of two research scientists who spoke about their work at a recent Academy public speaker series event. She was joined by Dr James Gong from Deakin University for ‘Surprising science: prawns and pipes’.

Dr Truong’s work focuses on sustainable ways to farm prawns.

“When we talk about increasing a farming industry, we also have to think about how we can do this sustainably – we have to think about the input and the outputs coming into this system and how we can minimise and better utilise waste to be used as inputs,” she said.

Prawns are notoriously unfussy eaters – discarded prawn heads and shells can be fed back to the growing stock. Prawns are also fed marine worms (which are reared on the farm’s waste); even our unwanted leftover food may one day become prawn food.

By implementing more sustainable circular economy strategies, such as turning waste into feed, we can improve the current linear approach to prawn production.

Shrimps look similar to prawns and belong to the same family of animals. The second speaker of the event, Dr Gong, researches prawns and shrimp from another angle: how taking inspiration from a shrimp can help fix leaky pipes.

 

“We lose about 255 gigalitres of water a year [in Australia], that’s enough treated water to supply 3.7 million people,” he said.

Detecting leaks in underground pipelines isn’t straightforward. Current techniques use a pulsed pressure wave with monitoring to detect ripples and reflections caused by pipe damage. However, the wave lacks precision so is not ideal for underground pipes. To better pinpoint damage, Dr Gong’s team sought inspiration from nature.

The snapping or pistol shrimp shoots a stream of water out of its large front claw. The stream travels at speeds up 100 km/h, enough to boil the water around it, resulting in a shockwave that stuns the shrimp’s prey.

“Inspired by this shrimp we developed a spark wave generator,” Dr Gong said.

A spark wave generator can be attached to a pipe and produces an electric spark in the water. Like the shrimp, this generates ‘cavitation bubbles’ that burst and create a pressure wave.

The result is a much more precise signal that can travel hundreds of kilometres down the pipe, all thanks to the humble snapping shrimp.

To find out about more nature-inspired solutions, see the next event in the Surprising Science series on 14 June.