Atlantic horse mackerel

The Atlantic horse mackerel has quite a slender, quite compressed body with a large head in which the rear of the upper jaw reaches the front of the eye and the lower jaw projects beyond the upper jaw. The eye has a well developed adipose eyelid. It has two dorsal fins, the first is tall The anal fin is about as long as the second dorsal fin and there are two separate spines at its anterior end. The lateral line has a total of 66–67 scales, of which 31–36 are scutes. It is dark blue in colour with silvery flanks and a white belly, there is a dark spot on the operculum. This species attains a maximum fork length of , although they are normally around and a weight of . ==Distribution==

The Atlantic horse mackerel occurs in the north and eastern Atlantic Ocean, the Mediterranean Sea and Sea of Marmara and the Black Sea. In the Atlantic it is found from Norway to South Africa where it may extend around the Cape of Good Hope along the southern African Indian Ocean coast Maputo in Mozambique. However, if Trachurus capensis is considered to be a valid species then this species is restricted to the north east Atlantic. It has been recorded in Cape Verde but is thought to occur there only as a vagrant. ==Habitat and biology==

The Atlantic horse mackerel is a benthopelagic species which normally occurs over sandy substrates at depths of , although it has been reported as deep as and it is sometimes found nearer the surface waters. ==Taxonomy and naming==

The Atlantic horse mackerel is the type species of the genus Trachurus but when Constantine Samuel Rafinesque created the genus in 1810 he used Trachurus saurus as the type species but Carolus Linnaeus had used the name Scomber saurus and had already described Scomber trachurus so Rafinesque's name was invalid. The genus Trachurus is part of the subfamily Caranginae of the family Carangidae, which is the largest family in the order Carangiformes. The generic and specific names are a compound of the Greek trachys meaning "rough" and oura meaning "tail", this appears to be an ancient name for horse mackerels, presumably in reference to the spiny scutes on the caudal peduncle. The common name horse mackerel has been said to derive from the belief that other fishes rode on its back but it may derive from the old Dutch word Horsmakreel which means a mackerel which spawns over a shallow or bank, a hors, and this was taken into English as "horse mackerel". The Cape horse mackerel (Trachurus capensis) is considered to be the subspecies T. trachurus capensis of the Atlantic horse mackerel by some authorities and it is thought that there is no adequate series of these specimens of this taxa along the coast of Africa available to confirm the validity of this taxon. ==Fisheries==

The Atlantic horse mackerel is fished for commercially using trawls, longlines, purse seines (using artificial light), traps and on line gear. In 1999 the Food and Agriculture Organization stated that the total catch reported to it was 322 207 tonnes with the largest catches being in the Netherlands and in Ireland. but the TAC is not in line with the scientific advice. There have been calls to create a management plan for the Atlantic horse mackerel in the North Sea but currently there are no specific management objectives for it. The stock needs to be assessed and management objectives should be set before the fishery can be shown to be sustainable. ==Conservation==

The IUCN classify the Atlantic horse mackerel as Vulnerable because even if there has been no decline in the population in European waters there have been greater than ninety percent declines off the West African coast which means that this species will have undergone a decline of at least 35–40% over the past three generation lengths, which are estimated at 30–35 years. The International Council for the Exploration of the Sea (ICES) classifies the population of this species as below the safe biological limit for exploitation. The populations are experiencing a slow decline with increased fishing pressure at the maximum sustainable yield since 2006 with low recruitment since 2004. ==Human uses==

The Atlantic horse mackerel is consumed fresh. It may be preserved by freezing, salting and drying, smoking and canning. It can be prepared by frying, broiling or baking. Nutritionally 100g of the flesh of the Atlantic horse mackerel provides 97 kcal of energy and is made up of: • Water: 77.4 g • Protein: 19.8 g • Fat: 2 g • Cholesterol: 64.4 mg • Total minerals: 1.3 g • Phosphorus: 224 mg In Iberia it may be prepared as an escabeche while some are exported to Japan as aji to be used in sushi. They are also an important ingredient in Sicilian cuisine. ==References==