New Zealand's largest fishery is hoki
Hoki (Macruronus novaezelandiae) are widely distributed throughout New Zealand waters from depths of 10 metres to over 900 metres, with the greatest abundance between 200 metres and 600 metres. Hoki spawn from late June to mid-September, primarily on the west coast of the South Island (Hokitika Canyon) and in the Cook Strait, with smaller amounts of spawning found in the Puysegur area and in Pegasus Canyon. Hoki grow to a maximum size of 130 cm and maximum age of 20 to 25 years. They reach maturity between 3 and 5 years of age. The age of the commercial catch varies among areas, but most fish caught are between 3 and 12 years old.
The hoki fishery operates throughout the year and includes both spawning and non-spawning fisheries. In 2020-21 the overall hoki catch was 91,665 tonnes of which 42,737 tonnes (47%) was taken from the western fishery.
History of the hoki stock
The New Zealand hoki Quota Management Area (HOK 1) covers all New Zealand Exclusive Economic Zone waters except the Kermadecs and is managed to a target biomass range of 35% to 50% of the unfished mature biomass (B0). Stock status is assessed annually assuming 2 separate but interlinked stocks, eastern and western, with separate catch limits set for each stock through a voluntary catch split arrangement.
Both Fisheries New Zealand and hoki quota owners are aware that the western hoki stock has been declining somewhat in recent years. The reasons are unknown, but a similar although more extreme scenario happened in the early 2000s – which no-one wants to repeat. The 2022 stock assessment estimated the biomass of the eastern stock to be above the upper bound of the management target range at 51% B0, whereas the biomass of the western stock was estimated to be at 28% B0, below the lower threshold of the management target range. Five-year projections using the 2021-22 catch limits estimated that both stocks would remain fairly constant over the next 5 years, assuming recent recruitment levels.
Management measures for hoki
In response to recent stock assessment results, and following public consultation, catch limit reductions were made in both 2019 and 2021. The 2021 decision reduced the western catch limit by 10,000 tonnes, to 45,000 tonnes, and increased the eastern catch limit by 5,000 tonnes, to 65,000 tonnes for the 2021-22 fishing year, resulting in an overall catch limit reduction of 5,000 tonnes.
Hoki quota owners have been concerned about potential declines in the western hoki in recent years and have voluntarily agreed to shelve quota (forego catch) even prior to the official TACC changes in 2019 and 2021. For example, the fishing industry:
- shelved 20,000 tonnes (plus carry forward) of western stock Annual Catch Entitlement (ACE) resulting in approximately 30,000 tonnes of HOK 1 ACE being transferred to a holding account that was not available for balancing against catch in the 2018-19 fishing year, and
- shelved 20,000 tonnes of HOK 1 ACE – 10,000 tonnes from each of the eastern and western stocks, creating an effective HOK 1 catch limit of 95,000 tonnes (western TACC = 45,000 tonnes) in the 2020-21 fishing year
- shelved 10,000 tonnes of HOK 1 ACE from the eastern stock, creating an effective catch limit of 100,000 tonnes split into 55,000 tonnes from the eastern stock and 45,000 tonnes from the western stock.
These measures have been developed to minimise and reverse the recent decline in the HOK 1 western stock biomass to ensure that the stock remains in good health and does not decline below the target range. In addition to the annual stock assessment and area catch limit, hoki are also managed using voluntary Hoki Operational Procedures consisting of:
- Hoki Seasonal Spawn Areas, which consist of week-long closures to hoki targeting in each of the main spawning areas during the spawning season, and
- Hoki Management Areas where vessel operators have agreed not to target hoki with vessels over 28 metres within 4 areas where there is relatively high abundance of small hoki.
The way forward for hoki
The next stock assessment for hoki is scheduled for 2023. It will include new data from the West Coast South Island and Chatham Rise trawl surveys, an acoustic survey from the Cook Strait and new information from the fishery including catch and effort data, age and length samples. The assessments routinely include research trawl survey information from the Chatham Rise and Sub-Antarctic and acoustic estimates from Cook Strait and the west coast of the South Island, as well as catch data and extensive length and age data. The 2023 assessment will provide updated information on the status of the stock, which will inform consideration of any further amendments to the management settings required to manage the population within the management target range.
