Horse Mackerel, Scad

Trachurus trachurus

Method of production — Caught at sea
Capture method — Demersal otter trawl
Capture area — North East Atlantic (FAO 27)
Stock area — Atlantic Iberian waters. Southern stock.
Stock detail — 9a
Picture of Horse Mackerel, Scad

Sustainability rating two info

Sustainability overview

Updated: July 2020.

The Southern horse mackerel stock is in a very healthy state and harvested sustainably. A precautionary management plan has been developed but is yet to be applied to this stock. The fishery is managed by an annual Total Allowable Catch (TAC) limit, which is combined with other species. This could lead to over exploitation of each of the combined species. The TAC has been consistent with scientific advice in recent years, catches have not exceeded the agreed TAC. Bycatch of Endangered, Threatened and Protected (ETP) species, and other non-target species have not been reported within this fishery, although high levels of bycatch can occur in demersal otter trawl fisheries. Demersal otter trawling has some habitat impacts.


Horse mackerel or scad belongs to a group of fish known as Carangidae. Adults are pelagic and form large schools in coastal areas with sandy substrate, usually in depths of 100-200 m, but reported to 500 m. Often shoals with juvenile herring. The Atlantic horse mackerel can be found in the north-eastern Atlantic from Iceland to Senegal, including the Cape Verde islands, and also in the Mediterranean and the Black Sea. Can attain a maximum length of 70 cm, but more commonly 22cm, with a maximum published weight of 2 kg. Matures at a length of around 24 cm (range 21 to 30 cm). Spawning takes place in summer in the North Sea, and earlier to the south of Biscay. Scad horse mackerel are batch spawners. Females lay 140,000 eggs, which hatch into 5 mm long larvae. Eggs are pelagic. They feed on fish, crustaceans, and cephalopods.

Stock information

Criterion score: 0 info

The stock is in a very healthy state and fishing pressure is well within sustainable limits.

The spawning–stock biomass (SSB) has been above MSY Btrigger (181,000 tonnes) over the whole time-series, with a continuous and steep increase in the last few years. SSB is currently at its highest level (1,102,627 tonnes). In 2020, the ratio of B:BMSY was 6.1. Fishing mortality (F) (0.028) has been below the maximum sustainable yield (FMSY) (0.11) over the whole time-series, and has remained relatively stable over the entire time-series. In 2019, the ratio of F:FMSY was 0.25. Recruitment (R) has been above the time-series average since 2011.

ICES advises that when the MSY approach is applied, catches in 2021 should be no more than 128,627 tonnes. The advice for 2021 has increased compared to the advice provided in 2020, because of the increasing trend in stock size and above average recruitments in recent years.

Horse mackerel in the northeast Atlantic is considered to be separated into three stocks: the North Sea, the Southern, and the Western stocks. The Western horse mackerel fishery is predominantly concentrated in the southern areas, close to Division 9a, where the Southern component is located. There is some overlap between the Western and Southern horse mackerel stocks, and possible mixing between populations, but this is undetermined.


Criterion score: 0.5 info

There are management measures in place, which are partly effective in managing the stock. A precautionary management plan has been developed but is yet to be applied.

A management plan (MP) has been proposed for this stock and was evaluated by ICES to be precautionary. However, ICES has been requested by the EU to continue to base its advice on the MSY approach, thus, the plan has not yet been applied.

In 2018, ICES evaluated the proposed long-term management strategy for this stock. The MP was considered to be precautionary, it was found that when the Harvest Control Rule (HCR) is applied, the stock is maintained at levels that can lead to catches around maximum sustainable yield (MSY). ICES advised that none of the elements of the HCR are in contradiction with ensuring that the stock is fished and maintained at levels that can lead to MSY, now and in the future. However, the EU has requested that ICES continues to provide catch advice based on the MSY approach, which leads to an increase of catch opportunities compared to the application of the MP. The catch advice for 2021 under the MSY approach, represents an increase of 262% in comparison with catches observed in 2019, if the advice would be based on the MP, then the increase of catches advised for 2021 in relation to actual catches in 2019 would be of 52%. The management strategy includes a +/- 15% stability clause which is only implemented after the first year of the plan being applied. Since the plan has not previously been applied, the 2020 TAC is not based on the plan and the stability clause would not apply in 2021.

Management of Southern horse mackerel, blue jack mackerel, and Mediterranean horse mackerel is under a combined Total Allowable Catch (TAC), which prevents the effective control of the single-species exploitation rates, and could lead to overexploitation of any of the mentioned species. The advice pertains to T. trachurus, while the TAC is set for all Trachurus species, including T. picturatus (blue jack mackerel) and T. mediterraneus (Mediterranean horse mackerel). Part of the catches consist of other Trachurus spp. than T. trachurus, and this percentage can vary from year to year. Estimates indicate that in 2019, less than 10% of the catch consisted of Trachurus spp. other than T. trachurus (2,377 tonnes). ICES considers that management of several species under a combined TAC prevents effective control of the single-species exploitation rates, and could lead to overexploitation of any of the species.

Since 2014, TACs have been set in line with advice. Compliance to the TAC is high. Observed catches have always been below the advised TAC in the available time-series. TAC for this species has not been limiting, in recent years this has been due to low market value and opportunities (landings on average 52% of the TAC; 2015-2019).

Information on current discarding indicates it is negligible.

Beyond TACs the fishery is managed by an EU minimum landing size of 15 cm for horse mackerel, which is significantly smaller than the length of maturity for the species. Length at first maturity is between 16 and 27 cm, but most commonly 21 cm. Consequently, horse mackerel are caught before they have had chance to reproduce.

The UK is due to leave the EU on 31st December 2020, and new UK Fisheries legislation is being developed during 2020. MCS will update ratings with new management information when new legislation comes into force.

In the European Union (EU), EU fishing vessels can fish up to 12 nautical miles of any Member State coast, and closer by agreement. There is overarching fisheries legislation for all Member States, but implementation varies between fisheries, Member States and sea basins.
The EU Common Fisheries Policy (CFP) is the primary overarching policy. Its key environmental objectives are to restore and maintain harvested species at healthy levels (above BMSY), and apply the precautionary and ecosystem-based approaches to fisheries management. To achieve the MSY objective, the MSY exploitation rate is supposed to be achieved by 2020, but this seems unlikely to happen.
The CFP also introduced a Landing Obligation (LO) which bans the discarding at sea of species which are subject to catch limits. Some exemptions apply to species with high post-capture survival, and where avoiding unwanted catches is very difficult. These exemptions are outlined in regional discard plans. Despite quota ‘uplift’ being granted to fleets under the LO, available evidence suggests there has been widespread non-compliance with the policy, and illegal and unreported discarding is likely occurring.
Multi-Annual Plans (MAPs) are a tool for implementing the CFP regionally, with one in place or being developed for each sea basin. They specify fishing mortality targets and ranges for the main targeted species, as well as lower biomass reference points. If populations drop below these points it should trigger a management response. The MAPs also empower Member States to jointly apply measures such as closures, gear or capacity limits, and bycatch limits. There is concern however that the MAPs do not provide adequate safeguards to maintain all stocks at healthy levels.
The EU Technical Measures regulation addresses how, where and when fishing can take place in order to limit unwanted catches and ecosystem impacts. There are common measures that apply to all EU sea basins, and regional measures that vary between sea basins. Measures include Minimum Conservation Reference Sizes (MCRS, previously Minimum Landing Sizes, MLS), gear specifications, mesh sizes, closed areas, and bycatch limits.
The Control Regulation, which is being revised in 2019, addresses application of and compliance with the above, e.g. keeping catches within limits, recording and sharing data, and satellite tracking of vessels over 12 metres (VMS).

Capture Information

Criterion score: 0.5 info

Southern horse mackerel is caught by demersal otter trawls, in the Iberian coast from the Strait of Gibraltar to Cape Finisterre in Galician waters (of the Spanish and Portuguese coast).

Southern horse mackerel is caught throughout the year and taken by directed fisheries, all catches are used for human consumption. Southern horse mackerel are targeted by a small number of fleets, which are defined by the gear type (bottom trawl, purse-seine and artisanal) and country (Portugal and Spain). Until 2011 the highest contribution to the total catches was, in general, from the trawl fleets. Since 2012, there has been a significant increase in the catches from the purse-seine. The contribution of the artisanal fleet from both Portugal and Spain is very small, respectively representing 4% and 1% of the total catches in 2019. The Portuguese artisanal fleet is mainly composed by small size vessels licensed to operate with several gears (gillnets, trammel nets, and lines). In 2019, 64% of catch was taken by purse seiners, 31% by demersal otter trawls, and 5% by the artisanal fisheries using other fishing gears.

Demersal otter trawling in the Iberian coast has some impact upon the seabed, as there is contact with the seabed and therefore risk to habitats. Impacts include abrasion (this pressure principally affects the seabed habitats and it is associated with bottom-contacting mobile fishing gear), and smothering, which can be cause by bottom trawling in soft sediment areas in this ecoregion. Within this area, the common skate, and less often spurdogs, are caught as bycatch in demersal trawl fisheries, but there have been no reports of bycatch of Endangered, Threatened or Protected (ETP) species within this fishery, therefore interactions are considered to be low. There have been no reports of bycatch of other non-target species, although, horse mackerel is a schooling species and often close to the sea floor, sharing the same habitat with other fish and invertebrate species. These species are mainly: snipefish, boarfish, blue whiting, European hake, sardine, blue jack mackerel, squid and pelagic crabs, which could be present in incidental bycatch. These species are found together in the stock area and most of them are commercially exploited, and fishing mortality for horse mackerel could affect the yield of all other species and vice versa.

Horse mackerel (T. trachurus), Mediterranean horse mackerel (T. mediterraneus) and blue jack mackerel (T. pictueatus), are all found together and are commercially exploited in North East Atlantic waters.

Young horse mackerel are a feeding resource consumed by several demersal, benthic and pelagic predators present in the distribution area like hake, monkfish, rays and dolphins, but does not seem to be the favoured prey among the area predators. Some recent unpublished work suggests an increase in the predation pressure from hake on small to medium-size horse mackerel is probably reflective of the recovery of the hake stock coupled with the high abundance levels of horse mackerel. Horse mackerel is mainly a zooplanktivorous species and become ichthyophagic when they reach large sizes, also being less targeted by predators. Even though horse mackerel prey on fish as they grow, they show a comparatively lower consumption of fish, being euphausids (Meganyctiphanes norvegica and Nyctiphanes couchi) and decapods (Pasiphaea sivado) as the most important preys.

Horse mackerel in this area are vulnerable to the effects of changing climatic conditions, which will most likely affect the abundance, distribution and composition of fisheries catches.


Abaunza, P., Gordo, L., Karlou-Riga, C., Murta, A., Eltink, A.T.G.W., Garcıa Santamarıa, M.T., Zimmermann, C., Hammer, C., Lucio, P., Iversen, S.A., Molloy, J. & Gallo, E. (2003). Growth and reproduction of horse mackerel, Trachurus trachurus (carangidae). Reviews in Fish Biology and Fisheries, 13, pp.27–61. Available at [Accessed 10.07.2020]

Azevedo, M. Costas, G. and Mendes, H. (2017). Stock Annex: Southern Horse Mackerel (hom 27.9.a). Available at [Accessed 14.07.2020]

ICES (2019). Bay of Biscay and the Iberian Coast ecoregion – Ecosystem overview. In Report of the ICES Advisory Committee, 2019. ICES Advice 2019, Section 6.1, Available at [Accessed 14.07.2020]

ICES (2019). Working Group on Widely Distributed Stocks (WGWIDE). ICES Scientific Reports. 1:36. 948 pp. Available at [Accessed 09.07.2020]

ICES (2020). Horse mackerel (Trachurus trachurus) in Division 9.a (Atlantic Iberian waters). In Report of the ICES Advisory Committee, 2020. ICES Advice 2020, hom.27.9a. Available at [Accessed 14.07.2020]

ICES (2020). Working Group on Southern Horse Mackerel, Anchovy and Sardine (WGHANSA). Draft report. ICES Scientific Reports. 2:41. 513 pp. Available at,%20Anchovy%20and%20Sardine.pdf [Accessed 14.07.2020]

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MMO (2018). Statutory guidance: Minimum Conservation Reference Size (MCRS) in UK waters. Available at [Accessed 10.07.2020]