The whiting is a cod-like fish. It has an elongated body with a small head and a pointed snout. It can grow up to 70cm in length. It is most commonly found between the depths of 30m and 100m and inhabits all sea-bed sediment types, especially sandy or muddy. It is abundant in shallow, coastal waters around the coast of Northern Ireland. However the large majority of individuals are too small to be commercially landed and this leads to large numbers of smaller whiting being discarded as by-catch.

In brief

• Whiting is found all around the coast of Northern Ireland
• Whiting do not make extensive migrations so can therefore be found all year round in Northern Irish waters
• Listed as a UK priority species with a marked decline in the Irish Sea population
• Lives both within the water column (pelagic zone) and on the sea-floor, mostly on sandy or muddy bottoms but can also live on rock or gravel bottoms
• The main cause of decline for whiting has been from overfishing, which continues to be a problem in the form of discarding

Species description: Whiting is a slender bodied fish with a narrow pointed head and snout. The upper jaw is longer than the lower. The chin barbel that is present on many other family members is not present on adult whiting, while juveniles can have a minute barbel. The colour is variable but most commonly has a blue/green upper colouring and white/silver sides and belly. There is a black spot located at the base of the pectoral fin. It has 3 dorsal fins and 2 anal fins and can grow up to a maximum length of 70cm.

Life cycle: Juvenile whiting spend their early life in shallow water (5-30m). Very small whiting (<5cm) can often be found sheltering amongst the tentacles of live jellyfish. As juveniles, whiting mostly eat small crustaceans and some small fish, as they get larger their diet changes mainly to fish (sprat, herring, sandeels). Whiting breed between January and July in UK and Irish waters. Spawning takes place in shallow water (30m), where pelagic eggs are released.

Similar species: There are many members of the Gadidae family that are similar in appearance to the whiting. These species include, Cod, Haddock, Bib, Poor Cod and Norway Pout. However the species that it gets mistaken for most often is the blue whiting. The main differences between the two are the absence of the black spot at the base of the pectoral fin on the blue whiting, the lower jaw being longer than the upper jaw in the blue whiting and the colouring. The colour of the blue whiting is blue/silver on its back as opposed to blue/green on the whiting.

How to see this species: Whiting is regularly caught by Northern Irish trawlers and sea anglers. Small individuals can sometimes be seen very close to the shore (<5m) and therefore may be seen during shoreline recreational activities such as swimming, surfing or snorkelling.

Current status: The latest advice from the International Council for the Exploration of the Seas (ICES) states that the state of the stock is uncertain. Long-term information indicates that the present stock size is extremely low and likely to be well below previously defined safe biological limits. Landings have seen a declining trend since the early 1980s, reaching lowest levels in the 2000s. The Total Allowed Catch (TAC) for whiting for the UK; as set by the European Commission, in the Irish Sea is 46 tonnes. This is a very low number compared to historical landings data and has been set as such to protect future whiting stocks and let the current population regenerate. Advice on UK priority species from the Joint Nature Conservation Committee has stated that the last accepted assessments in 2003 showed that the Irish Sea stock of Whiting decreased by a factor of 10 between the 1980s and 90s.

Why is this species a priority in Northern Ireland?

• Whiting is listed as a UK priority species classed as suffering from a marked decline in the UK

Threats: The main threats to the UK and Irish whiting populations are from fishing were almost all whiting caught is now discarded due to fish being below the minimum landing size of 27cm. Of the Irish Sea whiting population a very small percentage is greater than 27cm in length and so anything caught under that size is discarded.

Action:

• UK and EU to implement effective fisheries management
• Undertake research into factors effecting recruitment levels and population response to climate change
• Reduce discards through use of technical measures. Two examples of these are the ‘Swedish Grid’ and an ‘Inclined separator panel’ which aim to dramatically reduce discards of fish by-catch in the Nephrops (prawn) fishery

Objectives: Avoid eating whiting from stocks which are depleted and where fishing is at unsustainable levels. The Marine Conservation Society’s ‘Good Fish Guide’ and the Marine Stewardship Council (MSC) have websites that can help consumer’s source sustainable seafood, see links below.

Conservation: Various measures have been taken in recent years in an attempt to decrease capture of juveniles in fishing nets in the Irish Sea. One of these measures was to decrease the fishing effort (days at sea) of the boats in the Northern Irish fleet. This was aimed to decrease discards and give the whiting population a chance to recover. Another measure that has been implemented is to have a total ban on whitefish fishing in the Western Irish Sea from mid-February to the end of April. This timeframe was selected to coincide with the spawning season of Cod but could also inadvertently benefit whiting.

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

iNaturalist: Merlangius merlangus at iNaturalist World Species Observations database.

WoRMS: Merlangius merlangus at World Register of Marine Species. Accepted name: Merlangius merlangus (Linnaeus, 1758). AphiaID: 126438.

Literature:

Maitland, P.S. and Herdson, D. (2010) Key to the Marine and Freshwater Fishes of Britain and Ireland. Bristol; Environment Agency 204.

Classification: Biota; Animalia; Chordata; Vertebrata; Gnathostomata; Osteichthyes; Actinopterygii; Actinopteri; Teleostei; Gadiformes; Gadidae; Merlangius