New Zealand is moving towards more sustainable fishing practices through new harvesting technology.



A joint venture between the industry and the Government is aimed at cutting the number of unintentionally caught fish and raising the value of those that are caught.



The technology, Precision Seafood Harvesting (PSH), has been developed by Sanford, Aotearoa Fisheries, Sealord, the Ministry for Primary Industries, and Plant and Food Research.



Rather than a traditional net, the new system uses a PVC liner that holds water within a tunnel, cutting stress, fatigue and physical damage to fish in the harvesting process.



The system allows small, unwanted fish to escape through the holes in the liner while underwater and keeps alive the fish that are caught.



Sanford chief executive and Seafood New Zealand chairman Eric Barratt said the "revolutionary" technology was the biggest step forward for the seafood industry in 150 years.



"What we've developed in New Zealand has huge benefits for fish stocks, the environment, consumers and New Zealand's seafood industry," he said.



The six-year programme has been kept under wraps for the past two years and has been trialled on Sanford, Sealord and Aoteroa Fisheries boats for the past six months.



It was expected to produce an economic benefit of $43.6 million a year to New Zealand by 2025, the Ministry for Primary Industries said.



The programme is funded through $26m invested by industry players and $26m from the Government. The Government had paid out $1.7m towards the Primary Growth Partnership programme by the end of June.



Sanford general manager of operations Greg Johansson said the new harvesting technology was just the start.



"This will lead to changes in vessel designs and layouts, the way we handle fish and get it to consumers," he said.



Plant and Food Research science group leader Alistair Jerrett said the new technology represented "New Zealand science in action" in the way the partners had collaborated and embraced change.



One of the main objectives was to ensure any animal that reached the surface was delivered back to the sea unharmed, if it could not be discharged at depth, he said.



Barratt said there were still kinks to be ironed out, but PSH was a good thing for the fishing industry.



"The biggest gain now is enhancing the productivity of the resource."



There would be more adequately-sized fish in the ocean if they were not being caught accidentally as juveniles, he said.



The fish that were caught would be of a higher quality, and without blood spots and bruising, he said.



Any vessels using the PVC liner needed a permit.



International patents had been acquired, and the parties involved were considering how they would eventually licence the technology out to other fishing companies in New Zealand and overseas, Barratt said.



WORLD FIRST



The industry is hailing the new Precisions Seafood Harvesting technology as a world first, but a Napier fisherman has been working on sustainable-fishing technologies with a similar objective for more than 10 years.



Richard "Rick" Burch, skipper of the Nancy Glenn II, has been developing nets that release unwanted fish, cut down on fuel use and reduce damage to the seabed from trawling.



He created a lighter net using a mesh setting called T90.



In essence, it changes the shape of the mesh from a diamond shape to a square, allowing for a greater escape of small fish.



As well as a reduction in uneconomic catch, it has less effect on the seabed as it is lighter.



Burch said he approached the Government about his work, but was turned away.



"I've been given the cold shoulder all the way along," he said.



Former minister for primary industries David Carter told Burch that the Government did not want gear restrictions as New Zealand had the best quota management system in the world.



Burch received funding from Maori fisheries trust Te Ohu Kaimoana, Ngati Kahungunu and the Guardians of the Sea to test the net in 2011.



However, the report on the testing was not released.



A portion of the report leaked this year said Burch's fuel bills were cut by up to 30 per cent in using the lighter net.



Between 52 per cent and 81 per cent of unwanted juvenile round fish, such as gurnard and red cod, were released using Burch's net.



Fisheries scientist Oliver Wade helped Burch with the science behind the new net and wrote the 30-page report.



Wade said he did not know it had not been made public, but said the whole thing was a "political minefield".



Wade's report said discards had not been recorded in New Zealand fishing data and authorities had no idea how much fish was being dumped.



Industry sources say the research pointed to about 200 inshore trawlers dumping about 4000 fish every trip for 35 trips a year - 140,000 fish.



Wade said the PSH programme was at a different level from what he and Burch had been developing.



The Napier project emphasised environmental benefits and any economic benefit was a bonus, Wade said.



However, the pair said they supported technology that made fishing more sustainable.



"Let's hope it's worth the taxpayers' money," Burch said.