The orange roughy's long life cycle makes it vulnerable to overfishing. Photo / Dean Purcell.
By Mary Argue of RNZ
A conservation group says the country’s largest orange roughy fishery is “past the brink” of collapse - but shutting parts of it down will not be enough to save it.
The Ministry of Primary Industries (MPI) has begun consultation on this year’s orange roughy catch limit, and has included the option to close the East and South Chatham Rise fishery.
In the early ’80s and ’90s, 20,000-30,000 tonnes of orange roughy were pulled out of the ocean every year in the area that spans the Chatham to the sub-Antarctic Islands, known as the Chatham Rise or ORH 3B.
But an MPI review this year estimated some orange roughy populations had reduced by up to 90%.
The Deep Sea Conservation Coalition said closing a section of the Chatham Rise fishery was a start, but not enough, and wanted to see a blanket ban on bottom sea trawling in all orange roughy breeding grounds.
Meanwhile, a case over orange roughy management decisions in 2023 will wrap up on Wednesday at the High Court in Wellington.
Citing the years following the “gold rush” of the ’80s and ’90s, Deep Sea Conservation Coalition’s Karli Thomas said the proposal to shut down parts of the orange roughy fishery was nothing new.
However, she said the current proposal was significant, given the size of the fishery, and a first in recent years.
After reducing the catch limit by 40% in 2023, from 7967 to 4752, due to sustainability concerns, MPI is asking for feedback on further reductions for the Chatham Rise orange roughy fishery.
The options include a catch limit reduction by 23%, 42% or 60%, with the fourth option seeing the closure of the sub-fishery, the East and South Chatham Rise, and the fastest return to healthy stock levels.
Thomas said her group would submit in support of the fourth option, but was sceptical that alone would save the fishery when modelling suggested some parts of it were already collapsed.
“We’re definitely past the brink.
“All the modelling is showing that 80% of the population has gone, in some cases, more than 90% is gone, and that’s generally considered the point of collapse for a fishery.”
She said the fishery’s “disastrous state” was a reflection of poor management and wanted to see a complete ban on bottom sea trawling of the fish’s breeding grounds and habitat - the impacts of which, she said, were twofold.
“Its habitat is being destroyed, because bottom trawls basically plough through coral gardens, and secondly, these fish are being targeted in the very places - the seamounts (underwater mountains) - they go to breed.
“So, if we’re also disrupting their life cycle, the fish really just don’t stand a chance.”
She said a single orange roughy trawl brought up six tonnes of coral last year.
MPI director of fisheries management Emma Taylor said bycatch of that scale, while unfortunate, was very rare.
“There are a range of measures in place to minimise the effect of fishing on coral and other habitats, including closures to prevent dredging and trawling on 32% of New Zealand’s seabed.”
Despite a catch limit of 4752 tonnes in the 2023-2024 year, only 2691 tonnes of orange roughy were reportedly caught.
The figures followed a gradual increase in catch limit size, after a quota low of 3600 tonnes in 2012-2013.
An MPI survey of orange roughy stock at the East and South Chatham Rise in 2023 found stock levels were either “flat or declining” and inconsistent with a previous assessment.
That assessment was later rejected.
Taylor said the uncertainty about the state of the orange roughy stock led to the precautionary and significant 40% catch limit reduction.
The management decisions in 2023 are currently being challenged in the High Court at Wellington, with the Environmental Law Initiative claiming the Minister of Oceans and Fisheries failed to consider the harmful effects of bottom trawling in the Chatham Rise.
Taylor said in the time since, there had been significant work done to update the model used to assess the fishery, “as well as acoustic surveys and other research into the state of the fishery”.
New information showed more needed to be done to put the “fishery back on track to meet sustainability targets”, she said, and Fisheries New Zealand was asking for public feedback on a range of options - including closure.
A May 2025 assessment estimated orange roughy stock levels between 8-18% of the original biomass (population).
The target management range is 30-50%.
Taylor said orange roughy fisheries had been closed in the past due to concerns about sustainability, as had other fisheries.
“Following this consultation, we will prepare advice for Fisheries Minister Shane Jones to make decisions on any changes, which would come into effect for the fishing year starting 1 October 2025.”
Consultation runs until July 28.
The orange roughy, which lives at depths of up to 1.5km, is slow growing and can live up to 120-130 years, with some reaching more than 200 years old.
Thomas said their long life cycle made them particularly vulnerable to overfishing.
She said that although they began breeding in their mid-20s to 30s, it was not until they were in their 70s or 80s that they spawned every year.
She said the ocean had an amazing ability to recover, but it would likely take a human lifetime for the orange roughy to bounce back.
- RNZ