Hauteur, Jack mackerel, Horse jack mackerel, Horse mackerel, Slender jack mackerel
Commercial fisheries occur for three species of jack mackerel: Greenback horse mackerel (Trachurus declivis), Yellowtail horse mackerel (T. novaezelandia), and Chilean jack mackerel (T. murphyi). However, commercial catches and management of jack mackerel are not reported separately by species.
The high harvest volume makes jack mackerel a valuable part of New Zealand’s deepwater fisheries. A number of factors influence landing volumes in the jack mackerel fisheries including availability of annual catch entitlement for bycatch and changes in market price.
All species of mackerel can be caught by bottom trawl, mid-water trawl or by purse seine. Landings in JMA 7 represent the greatest proportion of total landings and are mainly taken by chartered trawlers. The jack mackerel in JMA 1 is mostly caught by purse seine in the Bay of Plenty and on the east Northland coast.
Jack mackerel is often combined with kahawai in the purse seine fishery. In an effort to conserve the kahawai quota, fishing companies will avoid these mixed schools, particularly at the start of the fishing season. Blue mackerel and skipjack tuna are fished in preference to jack mackerel in the purse seine fishery, causing the length of the jack mackerel season to be influenced by the availability of these species.
Jack mackerels have been included in the Quota Management System (QMS) since 1996. Before 1996, jack mackerels were considered part of the QMS, although ITQs were issued only in JMA 7. Jack mackerel in JMA7 is managed as part of New Zealand’s deepwater fisheries. JMA 1 is managed by the Inshore Fisheries Management Team as almost all catch of those species in this area is taken by the domestic purse seine fleet.
The risk assessment covers roughly 90% of all jack mackerel caught in New Zealand.
The risk assessment framework is used to assess the relative environmental risks of Australian and New Zealand wild caught fisheries on fish stocks and the aquatic environment.
Assessments are undertaken for each species according to multiple ‘units of assessment’ (UoAs). The UoA is a combination of target species/stock and the gear type used by the fishery. Each UoA is assessed against three components for target species, bycatch and ecosystems, and management systems. Each component has a number of performance indicators, which have associated criteria, scoring issues and scoring guideposts. For each UoA, each performance indicator is assigned a risk score according to how well the fishery performs against the scoring guideposts. The summary of risk scores by UoA are presented in the table below.
An assessment of the future ‘outlook’ over the short to medium-term (0-3 years) is provided against each component. Outlook scores are provided for information only and do not influence current or future risk scoring.
All risk assessments are conducted by an independent third party. The process only takes a few days and includes opportunities for management groups and government to provide input and peer review.
The information presented on this page is extracted from the independent species Risk Assessment Report.
Risk Assessment Summary
Component 1 of the risk assessment looks at the health of the population of target species including the current fishing effort and estimates a risk of overfishing.
Commercial catches and management of jack mackerel are not reported separately by species. This is complicated by the fact that the stock structure of the three jack mackerel species is uncertain, and the Quota Management Areas may not reflect distinct biological stocks. Although many of the systems and tools comprising an effective harvest strategy are in place, stock status is unknown and there is no reliable index of abundance. The Ministry for Primary Industries concluded that it is not known whether catches at the level of the current Total Allowable Commercial Catch (TACC) or recent catch levels are sustainable in the long-term.
Very good information on fleet composition is available through the QMS arrangements and observer coverage, particularly in the JMA 7 region, has been relatively high in recent years. Harvests are closely monitored through the QMS reporting arrangements, with validation from observers. Estimates of illegal fishing are not available, but anecdotal evidence suggests it is insignificant.
The main weakness of jack mackerel against this indicator is the absence of a reliable measure of stock abundance. Assessments, particularly for JMA 1, have been infrequent and it is not clear how they have actively supported the harvest control rule.
Bycatch and ecosystems
Component 2 of the risk assessment looks at the risks around bycatch species and other environmental impacts of the fishery.
Some trawl bycatch of jack mackerel has been reported in JMA 1. Several bycatch issues have been reported for the JMA 7 fishery. Blue mackerel is a large bycatch fishery that operates for several months of the year, and includes other bycatch species taken in this fishery such as barracouta, gurnard, John dory, kingfish, and snapper. For the JMA 1 purse seine fishery, impacts on main other species are limited. For the JM A7 fishery, these measures form at least a partial strategy which is expected to maintain JMA 7 at levels highly likely to be above the point of recruitment impairment. The results of independent research sampling and periodic stock assessments on main other species provide an objective basis for confidence that the strategy will work.
The main potential endangered, threatened and protected species interactions in the jack mackerel fisheries are with seabirds and some marine mammals.
The available evidence indicates it is highly unlikely the trawls involving jack mackerel will hinder recovery of seabird species. In the most recent assessment, only one species of seabird, black petrel, had a median risk ratio higher than 1 (or upper 95% confidence limit higher than 2). There have been no observations of black petrel captures in jack mackerel trawl fisheries. For other species, the current level of interactions in the jack mackerel fisheries appears highly unlikely to hinder recovery.
It appears highly unlikely that the level of incidental captures of New Zealand fur seals in the jack mackerel trawl fisheries are hindering recovery.
Given the uncertainty around setnet and inshore trawl fishery mortalities, cumulative fisheries risk for common dolphins remains highly uncertain in the pelagic jack mackerel trawl fisheries. The final results from the New Zealand Marine Mammal Risk Assessment are expected in 2017 and future scoring should take these into account.
Component 3 of the risk assessment looks at the risks around the management systems of a fishery.
The Fisheries Act 1996 and subsequent amendments provide a binding legislative and legal framework for delivering the objectives of Components 1 and 2. Sections 10, 11, and 12 of the Fisheries Act establish the requirements for the decision-making process, and Section 10 further requires the use of best available information for all decisions. This results in measures and strategies to achieve the fishery-specific objectives. The Fisheries Act requirement for best available information leads to scientific evaluation in advance of decisions. The Fisheries Act further requires consultation with such persons or organisations as the Minister considers are representative of those classes of persons having an interest in the stock or the effects of fishing on the aquatic environment in the area concerned including Maori, environmental, commercial, and recreational interests.
While objectives broadly consistent with Components 1 and 2 are specified in the Act and Fisheries 2030, and are therefore implicit in the fishery specific management system, it is not clear that explicit short and long-term objectives for inshore jack mackerel fisheries are in place at this stage. On the other hand, the management system for deepwater jack mackerel fisheries has explicit short and long-term objectives which are set out in long-term plans e.g., Fisheries 2030, National Deepwater Fisheries Plan and Annual Operational Plans. Objectives are subject to an annual review report and are explicit within the fishery’s management system.
Summary of main issues
Main issues highlighted by the assessment are:
- Stock assessments for jack mackerel are complicated by the reporting and management of three species under a single code. The stock structure of the three jack mackerel species is uncertain and further complicated with the effect of the relatively recent (1987) invasion of murphyi on stocks of the New Zealand jack mackerel.
- The most recent assessment for JMA 1 was undertaken in 1993. It is not known whether catches at the level of the current TACC or recent catch levels are sustainable in the long-term
- The most recent assessment of JMA7 indicated that overfishing was unlikely to be occurring, although the position of the stock against reference points is unknown. A stock assessment is planned for 2017-18.
- The JMA7 fishery has a bycatch of common dolphins. Preliminary risk assessment results examining cumulative risk to common dolphins across all New Zealand fisheries are highly uncertain with an estimated risk score that may be less than half the Population Sustainability Threshold or may exceed the Threshold by a factor of two. Final risk assessment results are expected in 2017.
The outlook below provides a qualitative judgement about the likely future performance of the fishery against the relevant risk assessment criteria over the short to medium-term (0-3 years). Assessments are based on the available information for the species and take into account any known management changes.
- Target species (JMA1_PS) - Uncertain: Uncertain stock status; no recent stock assessment.
- Target species (JMA7_Trawl) - Uncertain: Stock assessment planned for the 2017/18 financial year.
- Bycatch and ecosystems (JMA1_PS) - Stable: No major changes to existing bycatch and ecosystem arrangements are expected.
- Bycatch and ecosystems (JMA7_Trawl) - Uncertain: Final outcomes of the Marine Mammal Risk Assessment are expected in 2017.
- Management systems - Stable: No major changes to existing management system arrangements are expected.