Hake is the only member of the family Merlucciidae in European waters. It is a cod like deep water fish and was once included in the cod family but has been designated its own family status. The characteristics for this predatory fish are its black mouth and gills as well as its pointed head. It is a valuable resource for many fisheries and is landed as targeted or by-catch.

In brief

• Hake is a migratory species and can be found throughout the Irish sea.
• Prefers muddy and rocky habitats.
• Lives at depths between 150-550 m. Seen all year round in fishermen’s trawls, at fish markets and in the supermarket.
• Has high quality flesh and is valued commercially.
• Main cause of decline is overfishing and high numbers of discards of juveniles.
• Slow growth and late maturity makes hake prone to overfishing.

Species description: Hake has a slender body a large head and snout, and powerful large curved teeth. It has well developed jaws and no chin barbell. The first dorsal fin is triangular in shape, the second dorsal and anal fin are long with a shallow dip two-thirds along their length. The lateral line is straight, and it is greyish blue on top and silvery white on the sides and belly. The inside of hake mouth and gills are black. During the day hake remain near the bottom but at night they come to the surface in search of food. They feed mainly on fish and squids but the young eat crustaceans. Hake can reach a maximum size of 140cm and weight of 15 kg, but average size is closer to 45 cm.

Life cycle: Hake spawn in several batches from February to July in deep water typically more than 200 m. After the larval stage juveniles use the currents to carry them into shallow water with a muddy seabed. There are two major nursery areas, the Bay of Biscay and off southern Ireland. As hake become sexually mature (at around 3 years and 39 cm for males, and around 4 years and 47 cm for females) they disperse to offshore regions of the Bay of Biscay and Celtic Sea.

Similar species: There are no similar species to hake its shape and colouring is quite distinctive.

How to see this species: As hake typically lives in deep water it is unlikely to be seen except by fishermen though it can be kept in aquariums. It is more likely to be seen at fish markets or in the supermarket.

Current status: Declining. Although there is no clear evidence of multiple populations in the Northeast Atlantic scientists assume two stock units of hake, the Northern and the Southern. Hake in Northern Ireland are incorporated into the Northern stock. There is no evidence of spawning or nursery grounds in Northern Irish waters. Being a migratory species hake is widely distributed and can be found throughout the Irish Sea. ICES states the number of mature fish able to reproduce is increasing in the Northern stock. However although the fishing mortality, which is the number of fish being removed by fishing, is decreasing it is still above a target defined by fishery scientists as the level at which the species can be fished sustainably. Spawning stock has been declining since 2016. Recruitment levels are variable.

Why is this species a priority in Northern Ireland?

• Criterion 2: Decline based on available data and expert judgement.

Threats: The main treat is overfishing as hake is caught in mixed fisheries, discards of juvenile hake can be substantial in some areas and fleets. Since hake is a late maturing fish the high numbers of discards of juvenile fish will ultimately pose a threat to the population.

Action: Records of new sites for this species, with details of habitat and population are always valuable. Observations with a photograph can be recorded using iNaturalist, find the MBDP-NI iNaturalist project here.

Alternatively, records can be sent to CEDaR, National Museums Northern Ireland, 153 Bangor Road, Cultra, Holywood, County Down, BT18 0EU. Tel 028 9039 5257, e-mail cedar.records@nationalmuseumsni.org, or via the online portal.

Objectives:

• Selecting different mesh sizes of fishing nets to conserve juvenile fish
• Maintain the number of viable populations of the species
• Maintain the range of the species
• Establish appropriate management on appropriate historic sites
• Choose seafood from sustainable sources in order to promote sustainable resources of hake.

Conservation:

• In 2009 the European commission adopted a long-term plan to improve the state of the northern hake stock in EU waters.
• A recovery plan was agreed by the EU in 2004 with the aim of increasing the number of fish able to reproduce and reducing the number of fish being discarded.
• Mesh sizes have been increased in areas where juvenile hake were thought to be distributed.
• Designated under the following: NERC Act (2006), Species of Principal Importance for the purpose of conserving biodiversity in England (section 41) and Wales (section 42).
• Scottish Biodiversity List 2005 of species of principal importance for biodiversity conservation.
• 2007 UK list of Priority Habitats and Species.
• Included in the UK Biodiversity Action Plan under the Grouped Plan for commercial marine fish.

Distribution Map from NBN: Merluccius merluccius at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Merluccius merluccius at iNaturalist World Species Observations database.

WoRMS: Merluccius merluccius at World Register of Marine Species. Accepted name: Merluccius merluccius (Linnaeus, 1758). AphiaID: 126484.

Classification: Biota; Animalia; Chordata; Vertebrata; Gnathostomata; Osteichthyes; Actinopterygii; Actinopteri; Teleostei; Gadiformes; Merlucciidae; Merlucciinae; Merluccius