Prize-winning net offers young fish an emergency exit
A trawler net that contains an innovative 'emergency exit' for juvenile fish should get its first sea trials early next year after winning a prestigious award.
Dan Watson, an engineer, won the £10,000 James Dyson Award for student inventors with a fishing net that is fitted with rigid plastic rings that not only allow small fish to pass through without injury, but lights up to show them which way to go to get out of the net.
By lighting up, he said, the ring 'is like an emergency exit sign' just those that can be found in public places such as cinemas and nightclubs to help people get out in an emergency, especially in the dark.
The invention, if trials are successful, should help fishermen reduce the number of juvenile fish that they catch. Such fish are often unmarketable and their capture damages stock levels because they die before they get a chance to breed.
James Dyson, best known for inventing a bagless vacuum cleaner, said: 'This tangible technology approaches a serious environmental problem, we should celebrate it. SafetyNet shows how young graduates like Dan can tackle global issues ignored by established industries in new and inventive ways.'
Mr Watson developed his SafetyNet as a potential solution to reducing overfishing and discards. An estimated 1.3 million tonnes of fish from the North East Atlantic are discarded annually, according to the United Nations' Food and Agriculture Organisation, and many are juveniles that are too small to be marketed.
Escape rings were his answer to unwanted catches of small fish after reading up 30-years' worth of scientific literature on fishing and fish behaviour. Fish that try to get through the mesh are often damaged because there is more friction and because the net can flex whereas the plastic rings stay rigid and have a smoother surface. In effect, they keep a hole open in the mesh without allowing the larger, marketable fish out.
Making the rings light up under water utilises the behaviour of the fish as they tend to be attracted by lights. The lights are self-powered, extracting energy from movement in the water, so do not need batteries.
Mr Watson said the lights probably have a double effect. Fish that are unaware they are in a trawler's net and are in imminent danger are thought to head towards the light out of curiosity, while those aware they are under threat see them as a likely escape route.
While developing the net he contacted fishermen, mainly those in Peterhead and Fraserburgh, who proved to be 'really helpful' in explaining the problems to him and how fish and trawls behave in the seas.
The nets went through several models as different prototypes were tested for strength, durability and low cost – aluminium, for example, was contained in an model of the rings but proved to deteriorate rapidy in water – and is now confident SafetyNet will work.
'The next step is a sea trial,' said Mr Watson. He is in talks with three fisheries research institutions, in the US, UK and Scandinavia, and expects trials to begin early in 2013. It is designed to work at depths of up to 200 metres (656 feet) but could be effective as deep as 1,000m (3,280 feet).
He was delighted to win the James Dyson Award which he said has provided a 'really useful injection' of cash and has provoked international interest in his invention.
A spokeman for the James Dyson Foundation said the invention was 'a perfect example of the 'tangible technology' that James Dyson is so passionate about' in providing engineering solutions to 'real world problems'.
Mr Watson first developed the escape rings as a project which formed part of his mechanical engineering degree at Glasgow University. He continued working on it during his masters degree at the Royal College of Art and now splits his time between work as an engineer and developing the net.
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