Engineering a prototype juvenile fish sorting system

The use of 3D printing and laser cutting equipment, along with much research, has combined to create a prototype juvenile fish sorting system. Developed by University of Canterbury Master of Engineering student Stefano Barfucci as part of a NIWA-led project, it offers an innovative way to allow undersized juvenile fish to escape directly from the trawl net.

“I explored a number of different designs as part of this research, using 3D printing and laser cutting equipment at UC’s Department of Mechanical Engineering. I was also able to test some of the concepts within a flume tank at the university to simulate ocean conditions,” says Barfucci.

The most promising concept was inspired by a cage system devised by Napier fisher Karl Warr. Barfucci further refined that system to develop a practical, lightweight prototype that can be fitted to traditional mesh netting.

“The solution I came to was cut from plastic panels. Laser cutting was great because it meant we could rapidly prototype and cut shapes in the panels that were sized correctly for the different morphologies of fish species that were being trawled for.”

The research by Barfucci was supervised by Professor Mark Jermy and Associate Professor Don Clucas.

“He has come up with a simple piece of equipment that could easily be mass produced and that fishers could use to avoid catching fish that are not required,” says Clucas.

When asked what adjustments he would like to make when producing the system again, Barfucci says that increasing the length of the system would give more opportunities for fish to escape. By also changing the opening shapes, bycatch may be able to be reduced further.

“This system focusses on reducing bycatch of smaller species by sizing the openings so that only the small fish can escape,” says Barfucci.

“Although smaller fish species make up a large proportion of the bycatch it is also important to focus on releasing larger species such as stingray and sharks. This was the other part of the project and was a system that relied on an active imaging and releasing of fish as they swum through the net.”

Professor Jermy says that the research has been rewarding for all involved: “We’re really happy to be working on ways of reducing bycatch and it has been great to work with the fishing industry and NIWA.”

Image credit: University of Canterbury