Haddock

What it is

The haddock is a marine fish belonging to the gadoid family, which includes true cods. It possesses an elongated body that tapers towards the tail, with a wedge-shaped head profile where the upper jaw extends past the lower one. A small chin barbel is present. The skin colour ranges from dark grey-brown on top to silvery white below. A key identifying feature is a distinct black oval mark near the pectoral fin, often called the 'Devil's thumbprint', alongside a black lateral line. Adults typically measure between thirty and seventy centimetres, though specimens can reach ninety-four centimetres and weigh over ten kilograms.

Where it lives

Populations exist on both sides of the North Atlantic, with higher abundance in the eastern waters. In Europe, they range from the Bay of Biscay northwards to Spitzbergen and the Barents Sea, with dense stocks around Iceland, Norway, and the Faroe Islands. In North America, they occur from western Greenland down to Cape Hatteras, with significant commercial fishing off Cape Cod and the Grand Banks of Newfoundland. These groups are largely separate, showing little mixing between eastern and western Atlantic populations.

How it lives

This species lives on the sea floor at depths of ten to four hundred and fifty metres, preferring temperatures between four and ten degrees Celsius. They feed on bottom-dwelling creatures such as sea urchins, worms, and bivalves, occasionally taking small fish. Younger fish start by eating planktonic organisms before switching to benthic prey. Seals and larger predatory fish hunt them. Growth rates vary by region and have accelerated recently, with fish reaching maturity faster than in previous decades.

Breeding and life cycle

Haddocks spawn in winter and spring, with timing differing between Atlantic regions. Females release thousands of floating eggs that hatch within three weeks. Larvae drift in open water before settling to the seabed at around seven centimetres long. Maturity is reached at two to five years depending on location and sex. Spawning grounds include areas off Norway, Iceland, and Georges Bank. Smaller, younger fish often spawn in shallower waters closer to shore compared to older offshore stocks.

Fish and people

Haddock is a vital food source, sold fresh, frozen, dried, or canned. It is a staple in British fish and chips and Scottish suppers. Traditional smoking methods produce specific regional products like the Arbroath smokie and Finnan haddie. In North America, smaller young fish are marketed as scrod. The fish supports large industrial fisheries managed by international bodies to ensure sustainability. While some conservation groups raise concerns about trawling impacts, many stocks are certified as sustainable by independent councils.

Status and threats

Most assessed stocks in the eastern Atlantic are considered sustainably harvested according to scientific advice. Western Atlantic populations also show healthy management levels. However, historical overfishing caused declines in the late twentieth century, particularly in North American waters, where catches never returned to mid-century peaks. Recent recruitment has been low after a period of high productivity known as the gadoid outburst. Conservation efforts focus on limiting catch quotas and monitoring stock health to prevent depletion.

Relatives and look-alikes

The haddock belongs to the genus Melanogrammus, which contains only this single species. It is closely related to Atlantic cod and whiting, often caught in the same mixed fisheries. These gadoids share similar habitats and biological traits. The black shoulder blotch distinguishes it from other similar groundfish. Taxonomically, it falls under the subfamily Gadinae within the order Gadiformes.

Questions people ask about Haddock

Good reading and sources

• Cullen skink recipeBBC, Article

• Haddock on WikipediaEncyclopedia
• More photos on Wikimedia CommonsPhotos
• Wikidata recordOpen data