Mackerel

Scomber scombrus

Method of production — Caught at sea
Capture method — Handline
Capture area — North East Atlantic (FAO 27)
Stock area — Northeast Atlantic and adjacent waters
Stock detail — 1-8, 14, 9a: South West England (Cornwall)
Picture of Mackerel

Sustainability rating one info

Sustainability overview

Updated: November 2020

The Northeast Atlantic mackerel fishery is in a healthy state and fishing pressure is within sustainable limits.

This stock had been subjected to prolonged overfishing (above MSY) since 1990. In 2003 fishing mortality began to reduce, and has been below MSY since 2016. However, management is not cohesive, with major states unable to reach agreement on long-term strategies or catch limits. This has resulted in unilateral allocation of quotas and total catch consistently exceeding scientific advice. As a result MCS has decided to rate some of the major states separately, to highlight where differences in approach by some states are of significant concern.

The handline fishery in the southwest of England is particularly selective and has its own ‘ring-fenced’ quota allocation. Therefore, management of this component of the stock is considered to be relatively good.

Biology

Mackerel is a fast swimming species belonging to a group of fish known as the scombrid family, which are related to the tuna. They are found in brackish marine waters in depths of up to 1000 m (though more normally in depths of 0-200 m). Abundant in cold and temperate shelf areas, they form large schools near the surface. They overwinter in deeper waters but move closer to shore in spring when water temperatures range between 11 degrees and 14 degrees C. Mainly diurnal, they feed on zooplankton and small fish. Mackerel are batch spawners, they spawn mainly in March to July; the eggs and larvae are pelagic. After spawning, the adults feed very actively, moving around in small shoals. By 3 years old, most mackerel are mature (at a length of approximately 28 cm). Females shed their eggs in about twenty separate batches over the course of the spawning season. Juvenile mackerel grow quickly and can reach 22 cm after one year, and 30cm after 2 years. Mackerel can attain a maximum length of about 70 cm and weight of 3.4 may live for more than 20 years.

Stock information

Criterion score: 0 info

Northeast Atlantic (NEA) mackerel is in a good state and fishing pressure is within sustainable limits.

The spawning-stock biomass (SSB) is estimated to have increased since 2007, reaching a maximum of 5,161,009 tonnes in 2014. SSB has been declining since then, but, remained above MSY Btrigger (2,500,000 tonnes) since 2008. Estimated SSB for 2020 was 3,681,413 tonnes, slightly less than the previous year (3,731,510 tonnes). The ratio of B:BMSY was 1.46. The fishing mortality (F) has declined since 2003, and is estimated to have been below FMSY (0.26) since 2016. In 2019, F was 0.22 and the ratio of F:FMSY was 0.85. Recent recruitment has been strong: there has been a succession of large year classes since 2001, with year classes since 2011 estimated to be above average.

ICES advises that when the MSY approach is applied, catches in 2021 should be no more than 852,284 tonnes. The advised catch for 2021 is slightly lower (8%) than the advice for 2020 because there has been a downward revision of the 2019 SSB as well as a continued decline in SSB, though this has been partly offset by an upward revision of the FMSY value used for the advice.

The assessment was re-benchmarked in 2019. In 2020, ICES evaluated and revised the reference points for the stock, under which the new FMSY on which the current advice is based (0.26) is higher than the previous value (0.23). The assessment is very sensitive to input data and model settings so there is some uncertainty in the assessment. Consequently, there has been a decrease in the influence of contradictory data in the assessment.

NEA mackerel is assessed as one stock but comprises of three spawning components: the North Sea component, the Western and the Southern components, plus, an overlapping area of these last two components, the Bay of Biscay. Only the North Sea component is sufficiently distinct to be clearly identified as a separate spawning component.

The results of recent egg surveys, from 2019, displayed a 12% decrease in the relative contribution of the southern and western components of the mackerel stock, in comparison to 2016 estimates. SSB consisted of 2.29 (61%) million tonnes from the western component and 0.80 million tonnes (21%) from the southern component, a combined estimate of 3.09 million tonnes (of the ~3.73 million tonne SSB estimate for 2019). The biomass of the North Sea component increased in the 2017 egg survey, then estimated to represent 7% of the spawning stock. The relative contribution of SSB from this component is likely to have to have increased to ~18% of the mackerel stock (2019). The triennial North Sea egg survey, which was due to be conducted in 2020, has been postponed until 2021 due to the pandemic.

Catch and survey data from recent years indicate that the stock has expanded north-westwards during spawning and the summer feeding migration. The distributional change may reflect changes in food availability and may be linked to increased water temperature, and/or increased stock size.

Management

Criterion score: 0.25 info

There is no long-term management strategy for Northeast Atlantic (NEA) mackerel agreed by all parties involved in the mackerel fishery. There is no internationally agreed quota, recent catches have been substantially above scientific advice. However, the English handline fishery is relatively well-managed.

Currently there is no agreement on a management strategy covering all parties fishing mackerel, and unilateral allocation of Total Allowable Catches (when combined), have resulted in catches exceeding scientific advice for the stock as a whole: in 2020 (18%); 2019 (12%); 2018 (83%); 2017 (37%); 2016 (37%). Adherence to TAC is high.

However, in South-West England, the handline fishery has a ring-fenced quota accounting for a small proportion of the total fishery. This component of the fishery is considered to be relatively well-managed. Juvenile mackerel are protected within an area known as the Mackerel Box, off the Cornish coast in the South Western Approaches, created in 1981 and extended in 1989. In the Mackerel Box there is a ban on targeted fishing for mackerel by trawlers and purse seiners; handliners are the only fishermen allowed to target mackerel.

The minimum landing size (MLS) for mackerel is currently set at 20 cm for the western area (30 cm for the North Sea).


Both the EU and UK have fishery management measures in place, which can include catch limits, targets for population sizes and fishing mortality, and controls on what fishing gear can be used and where. In the EU, compliance with regulations has been variable, and there are ongoing challenges with implementing some of them. There was a target for fishing to be at Maximum Sustainable Yield by 2020, but this was not achieved. The Landing Obligation (LO), an EU law that the UK has kept after Brexit, requires all fish and shellfish to be landed, even if they are unwanted (over-quota or below minimum size). It aims to promote more selective fishing methods, reduce bycatch, and improve recording of everything that is caught, not just what is wanted. Compliance with the LO is generally poor and actual levels of discards are difficult to quantify using the current fisheries observer programme.

In the UK, it is too early to tell how effective management is, as the Fisheries Act only came into force in January 2021. The Act requires the development of Fisheries Management Plans (FMPs) (replacing EU Multi-Annual Plans) but there are no details yet on how and when these will be developed. FMPs have the potential to be very important tools for managing UK fisheries, although data limitations may delay them for some stocks. MCS is keen to see FMPs for all commercially exploited stocks, especially where stocks are depleted, that include:
Targets for fishing pressure and biomass, and additional management when those targets are not being met
Timeframes for stock recovery
Technologies such as Remote Electronic Monitoring (REM) to support data collection and improve transparency and accountability
Consideration of wider environmental impacts of the fishery

Capture Information

Criterion score: 0 info

The Northeast Atlantic (NEA) Mackerel fishery is international and, as such it is exploited by several nations using a variety of techniques determined by both the national fleet structure and the behaviour of the mackerel. An English handline fleet operates in the otherwise restricted area known as the Cornwall box.

As a widely distributed and migratory species, NEA Mackerel is exploited over a wide geographic range throughout the year. Significant fisheries extend from the Gulf of Cadiz, along the western and northern Iberian coasts, through the Bay of Biscay, South, West and North of the United Kingdom and Ireland, into the northern North Sea and the Norwegian Sea, and in more recent years have expanded north and west into Icelandic and east Greenland waters. In 2019, Norway accounted for the greatest proportion (19%) of catch followed by Scotland (15%), Iceland (15%), Russia (15%) and Faroe (7%). 80.4% of landing were by pelagic trawl; 19% purse seine; and 1% by other gears, such as handlines.

Fishing with hook and line (handline, tolling, lures, rod and reel) is one of the most sustainable and species selective fishing methods available, and has no impacts on the seabed.

The handline fishery is located off the southwest coast of England, from Start Point to Hartland Point within UK territorial waters; this falls within the International Council for the Exploration of the Seas (ICES) areas 7e-h. Most of the fishing occurs within 6-8 nautical miles of shore and targets mackerel from the western component of the stock. The main ports are Newlyn and Looe, with landings also taking place in Plymouth, St Ives, Mevagissey and other ports. The handline method uses either braided twine or strong nylon lines to which hooks are attached. Coloured plastic or feathers are attached to these hooks to attract fish and the line is weighted with lead. Each handline has 25-30 hooks. Since 1998 the fishery has been granted special quota allocation under authority of the Marine Management Organisation (MMO). Allocation is set at 1,750 tonnes or 0.83% of the UK quota, whichever is the larger. Up to 150 vessels can be fishing in winter. Most of these are under 10m. Many are 5-8 m single-handed open boats.

Within the area of the southwest Mackerel Box off Cornwall in southern England only handliners are the only fishers permitted to target mackerel. This area was set up at a time of high fishing effort in the area in 1981 by Council Regulation to protect juvenile mackerel, as the area is a well-known nursery. The area of the box was extended to its present size in 1989.

References

Anon (2017). Agreed record of conclusions of fisheries consultations between Norway, the European Union and the Faroe Islands on the management of mackerel in the Northeast Atlantic for 2018, London, 11 October 2017. 8 pp. Available at http://www.ices.dk/community/groups/Documents/EU-NorFaroe%20Agreed%20Record%20for%20Mackerel%20Oct%202017.pdf [Accessed on 02.11.2020]

Jansen, T. and Gislason, H., (2013). Population Structure of Atlantic Mackerel (Scomber scombrus). PLoS One, 8(5), pp.1-10. Available at https://doi.org/10.1371/journal.pone.0064744 [Accessed on 01.11.2020]

Moura, A., Muniz, A., Mullis, E., Wilson, J., Vieira, R., Almedia, A., Pinto, E., Brummer, G., Gaever, P., Goncalves, J. and Correia, A. (2020). Population structure and dynamics of the Atlantic mackerel (Scomber scombrus) in the North Atlantic inferred from otolith chemical and shape signatures. Fisheries Research, 230(105621). Available at https://doi.org/10.1016/j.fishres.2020.105621 [Accessed 02.11.2020]

ICES (2020). EU, Norway, and the Faroe Islands request for advice on the long-term management strategies for Northeast Atlantic mackerel (full feedback approach). In Report of the ICES Advisory Committee, 2020. ICES Advice 2020, sr.2020.07. https://doi.org/10.17895/ices.advice.7446. Available at http://ices.dk/sites/pub/Publication%20Reports/Advice/2020/Special_Requests/eufono.2020.07.pdf [Accessed 02.11.2020]

ICES (2020). Mackerel (Scomber scombrus) in subareas 1–8 and 14, and Division 9.a (the Northeast Atlantic and adjacent waters). In Report of the ICES Advisory Committee, 2020. ICES Advice 2020, mac.27.nea. https://doi.org/10.17895/ices.advice.5907. Available at http://ices.dk/sites/pub/Publication%20Reports/Advice/2020/2020/mac.27.nea.pdf [Accessed 02.11.2020]

ICES (2020). Stock Annex: Mackerel (Scomber scombrus) in subareas 1-7 and 14 and divisions 8.a-e, 9.a (the Northeast Atlantic and adjacent waters). Available at http://www.ices.dk/sites/pub/Publication%20Reports/Stock%20Annexes/2020/mac.27.nea_SA.pdf [Accessed 02.11.2020]

ICES (2020). Working Group on Widely Distributed Stocks (WGWIDE). ICES Scientific Reports. 2:82. 1019 pp. Available at http://doi.org/10.17895/ices.pub.7475 [Accessed 02.11.2020]