New Zealand hoki is available frozen in either skin-on or skin-off boneless fillets. Hoki flesh is off-white and when cooked is more flavorful than most other whitefish due to its higher fat content. Most New Zealand hoki exported to the United States is deep-skinned because there is a noticeable brown fat line. Premium center cut New Zealand hoki loins that lack the thin tail are also available from most processors. The highest quality New Zealand hoki is caught by factory trawlers from January through June and will have whiter flesh than hoki frozen on-shore, according to some buyers. Quality can vary considerably so buyers are advised to be sure of what they’re purchasing.
New Zealand hoki are related to cod and hake. Their bodies, which are covered with tiny scales, are elongated and compressed with a long, tapering tail. The dorsal and anal fins merge into the tail fin. There is no distinction between the tail and body. They have a bluish-green tinge on top of their bodies and are more silvery in color on the sides and belly. Hoki have large mouths and eyes.
This species can grow between three to four feet in length. Hoki usually weigh between three and four pounds but can reach upwards of 15 pounds. Females grow slower but become larger than males. Hoki can live for up to 25 years. Hoki have a relatively fast growth rate. They reach sexual maturity between three and five years of age. Spawning occurs during the winter and early spring. Females lay eggs and are thought to release more than one million eggs during spawning events. New Zealand hoki are carnivorous. They feed on small fish, especially lanternfish, crustaceans and squids. Hoki are preyed upon by pink cusk-eels.
New Zealand hoki inhabit the Pacific Ocean – particularly the temperate waters of New Zealand and southern Australia, including Tasmania. In New Zealand, the species is divided into two main biological stocks based on eastern or western spawning grounds. The eastern stock is found off the East Coast of the South Island, Memoo Bank, Chatham Rise, Cook Strait, and the East Coast of the North Island, while the western stock is found off the West Coast of the North and South Islands and areas south of New Zealand in sub-Antarctic such as the Puysegur, Snares, and Southern Plateau. In Australia, hoki are found from Newcastle, New South Wales to just north of Bunbury, Western Australia. There is thought to be little, if any, interaction between the New Zealand and Australian hoki populations – with some hoki in New Zealand being found to be genetically distinct from those in Australia.
Hoki live at or near the bottom of the ocean and are found at depths ranging from 164 to 2953 feet (50 to 900 meters) – although they are most abundant in waters between 984-1969 feet (300-600 meters). Juveniles will inhabit shallower waters and can be found in bays, inlets, and occasionally, even large estuaries. Adults are generally found in large schools in deep waters below 1312 feet (400 meters). They are often associated with shelf edges. Adults conduct annual migrations to spawning grounds and typically exhibit diurnal migrations – migrating up in the water column at night, and returning to deeper waters during the day.
Science & Management
The New Zealand government conducts scientific research on two separate stocks — the eastern and western stock — found in the country’s waters. This research, which includes estimating the number of hoki in each stock, helps to inform catch limits and overall management of the species. Scientists monitor the change in stock status from year to year as the number of young hoki that reach adulthood can vary. Other factors, such as changes in water temperature and annual catch, also affect the stock status.
New Zealand hoki are managed by the Ministry for Primary Industries (MPI) in New Zealand. Primarily caught using midwater and bottom trawl gears, New Zealand hoki are considered to be the most abundant commercial finfish species in New Zealand and the country's largest fishery since the 1980s. There are two stocks of hoki in New Zealand, an eastern that consists of the East Coast of the South Island, Memoo Bank, Chatham Rise, Cook Strait, and the East Coast of the North Island and a western that encompasses the West Coast of the North and South Islands and areas south of New Zealand in the sub-Antarctic such as the Puysegur, Snares, and Southern Plateau. Of these two stocks, there are four main hoki fisheries: West Coast of the South Island, Cook Strait, Chatham Rise, and the sub-Antarctic. Between 1995 and 2000, the western stock declined due to low recruitment. Since then, a stock-rebuilding plan has been introduced and the western stock has been rebuilt. Both stocks are now considered to be at target levels with recent stock assessments projecting biomass likely increasing slightly over the next five years.
The primary management tool in New Zealand’s fisheries management is the Quota Management System (QMS), which covers over a hundred commercially important species accounting for more than 600 different stocks. First introduced in 1986, the QMS is designed to ensure the long-term sustainable use of fishery resources by limiting the amount of fish that can be harvested. Under the QMS, each of the 600 plus stocks is assigned its own annual total allowable catch limit, or annual fishing quota, by the MPI. Each year, the MPI sets a single total allowable catch limit for New Zealand hoki under which the eastern and western stocks each get separate quotas. While both the eastern and western stocks are assigned separate quotas, both stocks are assessed simultaneously as individuals from both stocks can be caught in the same regions (such as Chatham rise) and it assists in overall fishery research. Access to the hoki fishery is determined by ownership of transferrable fishery quotas which can be bought or sold amongst users and allows owners to fish up to a certain proportion of the total allowable catch for the eastern and western stocks. Under the QMS, the New Zealand government has also purchased a portion of the quota and has transferred it to the Te Ohu Kaimoana (Treaty of Waitangi Fisheries Commission) in recognition of Maori rights to the commercial hoki fishery.
Among other management measures are:
General area closures – 30 percent of New Zealand’s exclusive economic zone (EEZ) is closed to all bottom trawling;
Fishery-specific area closures – four hoki management areas (HMAs) have been identified as important nursery grounds and are closed to hoki fishing as well as additional time and area closures;
Fishery vessel monitoring and observer coverage (when selected); and,
Bycatch reduction measures – mandatory crew training on techniques to reduce seabird bycatch, measures to avoid harming seabirds such as having bird-scaring devices, minimum mesh sizes to reduce the catch of juvenile hoki, and sea lion exclusion devices (SLEDs) use.
Hoki, often called blue grenadier in Australia, are managed by the Australian Fisheries Management Authority (AFMA) as part of Australia’s Southern and Eastern Scalefish and Shark Fishery (SESSF). The SESSF is a multigear/multispecies fishery, is the largest Commonwealth-managed fishery in terms of volume, and covers almost half the Australian Fishing Zone. Under the SESSF, the AFMA assigns annual fishing quotas, also called total allowable catch limits, for hoki, along with 33 other species/species groups. These quota species account for 80 percent of the total commercial catch in the SESSF. Quotas have been in place for hoki since the 1990s with the current total allowable catch for the 2017/2018 fishing season being set at 8765 tonnes. In the SESSF, fishers have Statutory Fishing Rights (SFRs) allowing them to fish a particular quota of the overall the total allowable catch. SFRs are transferable as well as can be leased to other users. Among other management measures for hoki include:
Restrictions on the number of vessels allowed in the fishery;
Reporting requirements (catch records);
Bycatch reduction measures – all trawling vessels must have a seabird management plan with freezer trawl vessels required to use seal exclusion devices to protect marine mammals. Additionally, bottom trawls must use a minimum mesh size to reduce the catch of juvenile fish; and,
Area closures to protect vulnerable species, spawning sites, and sensitive habitat.
Hoki are fast growing with high fecundity, making them fairly resistant to fishing pressure but their spawning aggregations off the west coast of New Zealand make them easy for fishermen to find.
The abundance of hoki in New Zealand is high, based on population assessments. However, there is conflicting evidence of declines in abundance over the past several years due to changing environmental and oceanographic conditions.
Habitat impacts (Wild)
Most hoki is caught off New Zealand by mid-water and bottom trawlers. Hoki go deeper down, closer to the ocean floor, as they mature. Mid-water trawlers cause little habitat damage, but bottom trawlers can have a substantial impact on the seafloor. Since most of the bottom trawling occurs in the muddy, gravel, and flat clay-like strata that are fairly resilient, the impact is minimized.
Bycatch in this fishery is considered moderate, and mostly consists of fish such as hake, ling, and southern blue whiting. The bycatch of seals, sea lions, and seabirds, remains a major concern in this fishery. Hoki fishing crews are required to undergo training in order to decrease seabird bycatch and fishermen are encouraged to use the Brady Bird Baffler, a special device that keeps birds away from a vessel. Minimum mesh sizes and area closures also prevent juvenile hoki bycatch.
Western and eastern hoki are managed separately in New Zealand by the country’s Ministry of Fisheries. Substantial measures are in place that make the fishery successful in achieving its conservation and sustainability goals. Those measures include catch limits, catch monitoring, thorough population assessments done annually, area closures, and sophisticated modeling.