Species Information

The word pelagic comes from the Greek πέλαγος or pélagos, which means open sea.

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Pelagic fish are normally found swimming in mid-water, where traditional fish like cod and haddock are found. Pelagic fish are generally found in large shoals. In fact, herring features in the Guinness book of records as the most numerous fish.

The main commercial pelagic species caught by Irish pelagic vessels include mackerel (Scomber scombrus), herring (Clupea harengus), horse mackerel (Trachurus trachurus) and blue whiting (Micromesistius poutassou).


Mackerel can be found in mid-water travelling in large dense, shoals, often at great speed and making very long migrations. It is a voracious, opportunistic feeder and feeds mainly on zooplankton, but also on some small pelagic fish. As a result it is a very oil-rich fish, building up high energy reserves during the spring and summer which it needs both for migration and subsequent gonad development during the following winter.

The majority of mackerel from the Irish quota is landed in January and February. Currently, the majority of this fish is purchased by the Russian market for smoking purposes.


Herring are found schooling in coastal waters, and have complex feeding and spawning migrations. They feed on small planktonic copepods and spend the day in deeper water, but rise to the surface at night and find their food visually. Schooling behaviour, silvery sides, excellent hearing, and very fast escape response all act as anti-predator devices.

Herring can be divided into several different stocks. The most important stocks in the East Atlantic are the winter-spawning Norwegian and Icelandic herrings, the autumn spawning Icelandic and North Sea herrings and the Baltic herrings.

The Irish quota for herring is split between January, February and the autumn months.

Horse mackerel

Adult horse mackerel form large schools in coastal areas with sandy substrate. They feed on fish, crustaceans, and cephalopods. They are not a well-known species in Ireland, and are mainly traded frozen. Seventy per cent of the Irish quota is caught in the spring fishery, from January to March, and the remainder is caught between October and December, in the autumn fishery.

Blue whiting


This species is relatively unknown on the domestic Irish market with large scale processing of the species in Killybegs since 2005. Unlike other pelagic species, blue whiting are low in fat as they are a member of the gadoid family (related to cod, haddock and whiting).

The primary target market for blue whiting is Africa, where it is a source of good value protein. In addition, a proportion goes to China for reprocessing.

The limited Irish quota is caught in February and March. Given the blue whiting resource is off the west coast of Ireland, a large proportion of the Norwegian catch is landed into Killybegs for processing.