A new form of commercial fishing - precision seafood harvesting (PSH) - has improved the survival rates for by-catch, scientists involved in the New Zealand project said.The system - which uses a large, flexible PVC liner with specifically sized holes along its length, allows undersized fish to escape before they are brought on board the fishing boat.The fish that are brought on board stay in better condition because they are still swimming in the liner when they are on the deck, the scientists said.PSH, which is backed by New Zealand's three biggest fishing companies - Aotearoa Fisheries, Sanford and Sealord, and the Ministry for Primary Industries - is the commercialisation phase after nearly 10 years of research."We were certainly hopeful that we'd improve the survivability rates for the fish we were catching, but already it's better than we expected," Alistair Jerrett, the science group leader from Plant and Food Research, said in a statement.Typically, snapper harvested with the PSH system have a 100 per cent chance of survival if they're fished from a depth of 0-20 metres, Jerrett said. "For snapper taken from deeper water, from 20-90 metre, the survivability number is 79 per cent and we're going to get better and better," he said.

The new fishing system is designed to reduce injury and death caused to unwanted bycatch in traditional nets such as this one. Dave Woods, the programme manager for PSH, said a fully functioning and commercialised PSH had huge potential to increase the sustainability of New Zealand's fisheries."The objective is to massively increase the proportion of small fish or unwanted by-catch that can be returned to the sea completely unharmed by our fishing," he said.Greg Johansson, chief operating officer at Sanford, said PSH changes the way fish can be brought to market, in terms of higher quality.

Aotearoa Fisheries, Sanford and Sealord are investing $26 million between them into the programme. The other half of the funding for comes the Ministry for Primary Industries, which is matching the industry investment under a Primary Growth Partnership.Scientists at Plant and Food Research are working with the fishing companies to develop and trial the technology on commercial fishing vessels. Woods said more work was needed to test PSH on more species and in a greater variety of conditions."We are only in the third year of a six year programme, so there is plenty of science still to be done," he said.