The recovery of orange roughy stocks is gathering pace.

Two orange roughy fisheries – one in the Tasman, the other centred in the Pacific and the sub-Antarctic – received substantial quota increases in the sustainability round that came into effect on October 1, the start of the new fishing year.

The Challenger Plateau fishery on the west coast off the top of the South Island, designated ORH 7A, has a 458 tonne increase, up 29 percent on the previous Total Allowable Commercial Catch of 1600 tonnes.

On the west coast in the Pacific Ocean, the orange roughy 3B fishery, which takes in part of the Chatham Rise and the sub-Antarctic islands within New Zealand’s 200-mile Exclusive Economic Zone, has an 11 percent boost. That represents a 681 tonne increase on the previous Total Allowable Commercial Catch of 6091 tonnes.

The decision announced by Fisheries Minister Stuart Nash provoked the predictable outrage from anti-commercial fishing activists dominated by Greenpeace, always quick to deny the science.

However, the catch increases are consistent with a 2018 global review of orange roughy, their fisheries, biology and management, commissioned by the United Nations Food and Agriculture Organisation.

Sustainable orange roughy fisheries are achievable, the review states.

Its authors, fisheries consultant Dr Geoff Tingley and NIWA scientist Dr Matt Dunn, are both Wellington based.

“In recent years there have been considerable but largely unscientific advocacy efforts by environmental non-government organisations (eNGOs) to make demersal trawling politically and environmentally unacceptable,” the report says.

“These efforts have been especially pronounced for the deepwater trawl fisheries such as those for orange roughy.”

But the authors state the three largest New Zealand roughy fisheries “have over a number of years been improved in both science and management”.

That led to the independent, third party sustainability certification by the Marine Stewardship Council, “a process that has seen the implementation of very conservative catch limits”.

Orange roughy fisheries were first developed in New Zealand in the late 1970s and were quickly over-exploited, peaking at an annual catch of around 50,000 tonnes in much of the 1980s, dropping to less than 10,000 tonnes in the last decade with a slow rebuild.

The review authors said roughy had been well studied, with more than 130 dedicated research surveys completed and numerous associated scientific studies.

New Zealand has open science review processes and publication of all relevant documents, including results from abundance surveys, stock assessments and supporting studies and stock projections.

“This high degree of transparency in science and management is of fundamental importance in enabling those interested in the fisheries, be they fishers, eNGOs, other science and management organisations, processors or retailers, to be able to have confidence in the management of the fisheries,” the report said.

Orange roughy are highly prized in the American market, as skinned fillets, and increasingly in China for whole fish.

New Zealand remains the world’s biggest orange roughy fishery, with a smaller amount caught in Australian waters. The only other commercial, targeted orange roughy fisheries are two in the high seas, in the southwest Pacific and in the southern Indian Ocean centred on Mauritius.

The catch limit decisions for the 2019-20 fishing year covered 20 stocks.

Seven fisheries, including hoki and tarakihi, had catch reductions, nine had increases and four remained the same.

Fish populations fluctuate naturally due to a wide range of factors and changes to catches under the maximum sustainable yield regime that drives the Quota Management System reflect that.