Management by stock levels

Fisheries New Zealand assesses and manages fish stocks using 4 performance measures:

• A hard limit – a biomass level below which a fish stock is considered to have collapsed and fisheries may need to be closed to rebuild at the fastest possible rate.
• A soft limit – a biomass level below which a fish stock is considered to be overfished or depleted and needs to be actively rebuilt, for example by reducing the total allowable catch.
• A target level – the level of biomass or a fishing mortality rate we want a fish stock to fluctuate around for the best balance between use and sustainability, while allowing for environmental variation.
• Overfishing threshold – a rate of stock removal that shouldn't be exceeded as it will lead to stocks falling below other performance measures.

The diagram below illustrates the relationship between the four performance measures.  The trace of stock abundance is the result of fishing just below the overfishing threshold. Stock abundance fluctuates around the management target and sometimes approaches the soft limit but never goes below this level, and stays far above the hard limit. Management action to ensure the stock continues to fluctuate around the management target would normally be taken at all points where the stock dips too far below the target.

Research helps set catch limits and other management controls

Fisheries New Zealand is serious about protecting New Zealand’s fisheries. We carry out research on fish stocks regularly. It helps us make sure they're healthy and sustainable.

New technology allows scientists to more accurately estimate the distribution and size of fish populations. This research helps the Government set annual catch limits and other management measures to ensure fishers don't catch too much. If the research shows that fish numbers have grown, catch limits may be increased. If estimated fish numbers have decreased, then catch limits may be reduced and other management measures introduced.

Performance measures and current stock status

All performance measures are important, but the key performance measure for determining the status of New Zealand’s fish stocks is the soft limit, a biomass level below which a stock is deemed to be overfished. We know the status of 159 stocks against the soft limit. Most of our fish stocks are in good shape (above the soft limit):

• 82.4% or 131 stocks and sub-stocks
• 90.9% of the total landings of assessed stocks by weight.

Of the 131 fish stocks that were above the soft limit in 2020, 101 (77.1%) were also above their management targets.

• Summary overview of 2020 fish stock status [PDF, 1.2 MB]
• 2020 report on the status of New Zealand’s fish stocks [PDF, 936 KB]

The 'December 2020 stock status table' shows the status of 399 of New Zealand's main fish stocks (or sub-stocks).

2020 stock status table [PDF, 226 KB]

Which stocks are included

Of the 399 fish stocks or sub-stocks included:

• 67 were assessed in 2020
• Numerous others have been assessed in previous years
• 394 are QMS stocks or sub-stocks
• 5 are non-QMS stocks or species that are Antarctic or highly migratory species.

Find out more about the QMS

Find out about catches and allowances for fish stocks

Nominal stocks not included

We haven't included 290 QMS fish stocks that:

• are in areas outside the main range of a species – set up for administrative purposes only
• have insignificant catch or catch allowance (generally close to zero tonnes)
• have little to no potential to develop as recreational, customary or commercial fisheries.

Download a list of nominal fish stocks [PDF, 27 KB]

Overfished stocks

28 stocks or sub-stocks are below the soft limit, meaning they are overfished:

• 3 stocks of black cardinalfish
• 5 stocks or sub-stocks of bluenose
• 2 stocks or sub-stocks of dredge oysters
• 2 stocks or sub-stocks of orange roughy
• 2 stocks or sub-stocks of scallops
• 2 stocks or sub-stocks of snapper
• 3 stocks or sub-stocks of tarakihi
• 1 stock or sub-stock each of hake, John dory, pāua, pipi, rock lobster, and shortfin eels
• Pacific bluefin tuna, southern bluefin tuna, and striped marlin, which are highly migratory species that are seasonally present in New Zealand waters and are managed by Regional Fisheries Management Organisations. Eight of these 28 stocks were also considered to be below the hard limit (collapsed).

Rebuilding overfished stocks

We're managing fisheries on overfished stocks so that they will rebuild towards target levels, for example by:

• reducing total allowable commercial catches of stocks managed through the Quota Management System (QMS)
• supporting management of highly migratory species under international arrangements.

Rebuilding east coast tarakihi

Tarakihi, Nemadactylus macropterus, on the east coast of New Zealand appears to comprise a single biological stock.  Tarakihi is a relatively long-lived species that reaches at least 40 years of age.  Females mature at 6 years, after which they produce large numbers of pelagic (floating) eggs several times during each protracted summer/autumn spawning season. Following a 7 to 12 month pelagic phase, where the fertilised eggs, larvae and juvenile fish tend to remain in surface waters, east coast tarakihi mainly settle in nursery grounds off the east coast of the South Island, primarily the Canterbury Bight and Pegasus Bay.  As they grow older, they move progressively further northward, with the highest proportions of older fish found off east Northland.

Research to monitor and rebuild tarakihi stocks

Stock assessments of east coast tarakihi are undertaken using a complex age-structured statistical model that accounts for gains and losses to the population, to provide an estimate of stock status in relation to the unfished level.  The model is fitted to several sources of data, including annual landings, growth rates, age structure of trawl surveys, and commercial catches from different regions, indices of relative abundance based on trawl surveys and standardised commercial Catch per Unit of Effort (CPUE).  

The first successful stock assessment for east coast tarakihi was completed in November 2017, and the assessment was updated in 2018, and again in 2019.

TACC reductions were implemented based on the stock assessment results in 2018 and 2019. The TACC reductions are predicted to rebuild the east coast tarakihi stock to the management target in 25 years. In addition, a voluntary industry rebuilding plan is being implemented, which includes a number of additional measures:

• a move-on rule and research into mesh selectivity to avoid the capture of juvenile tarakihi
• voluntary closed areas
• limits on catches from the eastern coasts of  the QMAs TAR1 and TAR2.

The way forward for east coast tarakihi

The next stock assessment for east coast tarakihi is scheduled for 2021. This new assessment, including new information on the age composition of the commercial catch and results from new trawl surveys, will provide information on the status of the stock, the response to previous management interventions, rebuild rates under current catch levels, and any further catch reductions required to rebuild the population within agreed time frames.

How we assess fish stocks

Fisheries New Zealand's Harvest Strategy Standard (HSS) guides the way we assess and manage fish stocks under the QMS.

The Harvest Strategy Standard [PDF, 237 KB]

Reports for individual species

Each year, we convene a large number of Fisheries Assessment Working Group meetings to assess the status of fish stocks using:

• scientific research (from contracted research providers)
• validated catch and fishing effort reports from commercial fisheries
• data from our on-board observer programme
• other relevant information.

This information is summarised in 2 annual fisheries assessment plenary reports – the main one in May (3 volumes) and one for rock lobsters and highly migratory species (1 volume) in November. The plenary reports provide information on our fisheries and the status of each fish stock.

Fisheries assessment plenary May 2020 – Volume 1: Introductory section and alfonsino to hake [PDF, 21 MB]

Fisheries assessment plenary May 2020 – Volume 2: Hoki to redbait [PDF, 27 MB]

Fisheries assessment plenary May 2020 – Volume 3: Red cod to yellow-eyed mullet [PDF, 32 MB] 

Fisheries assessment plenary November 2020 – Introductory section to yellowfin tuna [PDF, 28 MB]

Who to contact

If you have questions about fish stock status, email info@mpi.govt.nz