Haddock

• 1. Introduction

  ›

  The haddock carries a mark on its body that has been called the Devil's thumbprint. It is a dark oval blotch sitting just above the pectoral fin, and it is distinctive enough that scientists named the entire genus after it. Melanogrammus, from the Greek for "black" and "line", is the haddock's scientific home, and it is the only species that lives there.

  In the North Atlantic, the haddock has shaped fishing economies, kitchen traditions, and dinner tables from Scotland to Nova Scotia for centuries. It is the fish inside the newspaper-wrapped parcel at a British chip shop, the centrepiece of a Scottish fish supper, and the key ingredient in kedgeree, an Anglo-Indian dish that wound its way into British homes.

  But behind the familiar fillet is a creature with a surprisingly intricate life: migration routes that span hundreds of kilometres, a reproductive capacity that scales from 55,000 eggs in a small fish to nearly two million in a large one, and a growth history that shifted measurably over just a few decades. What drives those changes? And how did the haddock survive the collapse that nearly erased it from the western Atlantic? Those are the threads this documentary will follow.

• 2. The Body and the Mark

  ›

  Carolus Linnaeus first formally described the haddock in 1758, in the 10th edition of volume one of his Systema naturae, assigning it the name Gadus aeglefinus with a type locality simply listed as "European seas". A century later, in 1862, Theodore Nicholas Gill created the separate genus Melanogrammus, placing the haddock as its sole member.

  The fish that earned all this taxonomic attention has a silhouette shaped by its environment. Three dorsal fins run along the back, the first rising to a triangular point. The first dorsal carries 14 to 17 fin rays, the second 20 to 24, and the third 19 to 22. Below, two anal fins mirror the arrangement. The mouth is notably small and does not extend beneath the eye, which gives the snout a wedge-shaped profile distinct from the Atlantic cod, though the upper jaw still juts forward past the lower.

  The colouring divides cleanly between a dark grey-brown to near-black upper body and a dull silvery white beneath. A black lateral line curves slightly over the pectoral fins and contrasts sharply with that pale background. The oval black blotch beside it gave rise to the folk name Devil's thumbprint, and gave the genus its Greek-derived name.

  The specific name of the species, aeglefinus, is a Latinisation of egrefin and eglefin, the vernacular terms once used in France and England. The haddock thus carries its own cultural history in its scientific label.

• 3. A Life in Cold Water

  ›

  Haddock are demersal fish, spending most of their adult lives near the seafloor at depths between 10 and 450 metres, though they are most commonly found between 80 and 200 metres. They prefer temperatures of 4 to 10 degrees Celsius and settle over substrates of rock, sand, gravel, or shells.

  Reaching sexual maturity takes years. In most populations, males mature at 4 years old and females at 5. The North Sea population is an exception, maturing faster: males at 2 years and females at 3. Once mature, females produce eggs in numbers that scale with their size. A fish measuring 25 centimetres carries around 55,000 eggs; one at 91 centimetres can carry close to 1,841,000.

  Spawning in the northwestern Atlantic runs from January to July, while the northeastern Atlantic season is February to June, peaking in March and April. Eggs are pelagic, measuring 1.2 to 1.7 millimetres across, and hatch within one to three weeks. The larvae remain in open water until they reach roughly 7 centimetres, at which point they descend and adopt the bottom-dwelling habit of the adults.

  Growth rates vary considerably by region. A one-year-old haddock may measure 17 to 19 centimetres; at two years, 25 to 36 centimetres; and at 13 years, 75 to 82 centimetres. The record individual was 94 centimetres long and weighed 11 kilograms. Haddock typically live around 14 years.

  Not all larvae stay near where they were spawned. Some hatched off the west coast of Scotland are carried into the North Sea by currents passing through the Fair Isle-Shetland Gap or around the northeast of Shetland.

• 4. What Haddock Eat and What Eats Them

  ›

  Larval haddock feed on copepods, ostracods, and limacina in their earliest stages. As they grow, their prey shifts toward amphipods, euphausiids, invertebrate eggs, and the zoea larvae of decapods. After settling to the seafloor, the diet shifts again toward benthic prey.

  Adult haddock feed primarily on sea urchins, brittlestars, bivalves, and worms. When smaller fish are available, haddock take them opportunistically, targeting capelin, sandeels, and Norway pout. This flexibility in diet has helped the species occupy a broad ecological niche across the North Atlantic.

  Juvenile haddock face their own predators. Larger demersal fish, including other members of the cod family, prey on young haddock. Seals pursue the larger fish.

  Among the most remarkable threats is the cod worm, Lernaeocera branchialis. This parasite begins its life as a free-swimming copepod larva. It first infects a flatfish or lumpsucker, clinging with grasping hooks and penetrating the host with a thin filament to feed on its blood. After mating on the lumpsucker, the fertilised female moves to a cod or a cod-like fish such as a haddock. There it metamorphoses into a wormlike body and attaches to the gills. The front portion of the parasite then drives deeper, entering the rear bulb of the host's heart and branching into the main artery, extracting nutrients from the fish's blood while sheltering under the gill cover.

• 5. Changing Populations

  ›

  The haddock stock experiences periodic surges in productivity. Notably high years of recruitment occurred in 1962 and 1967, with lesser peaks in 1974 and 1999. These strong year classes push the species into a more southerly distribution and significantly increase the biomass of the spawning stock. High fishing mortality has historically prevented these periodic recoveries from leaving a lasting mark on the population.

  From the 1960s into the early 1980s, haddock, Atlantic cod, and whiting all experienced above-average recruitment simultaneously. Researchers have described this period as the gadoid outburst. Recruitment remained strong into 1999, but has since fallen to very low levels.

  Growth rates have also shifted. In the decades leading up to 2011, haddock grew faster than historical records had shown, reaching adult size at younger ages. More recently, however, growth rates have slowed. One proposed explanation points to an unusually large year class produced in 2003; the degree to which those younger, faster-growing fish have contributed to the population's reproductive success remains uncertain.

  In the western Atlantic, the commercial catch ran to approximately 40,000 to 60,000 tonnes per year between 1920 and 1960. It collapsed sharply in the late 1960s, dropping to between 5,000 and 30,000 tonnes annually, and landings have not recovered to earlier levels despite some good years after 1970.

• 6. Fishing Grounds and Governance

  ›

  Haddock is caught year-round using Danish seine nets, trawlers, long lines, and gill nets, often alongside cod and whiting in mixed-species fisheries. The main eastern Atlantic grounds extend across the Barents Sea, Iceland, the Faroe Islands, the North Sea, the Celtic Sea, and the English Channel.

  Eastern Atlantic landings fluctuated between 200,000 and 350,000 tonnes annually over the period 1980 to 2017. During the 1980s, Rockall provided the largest portion of that catch. From around 2000, the Barents Sea overtook it. The International Council for the Exploration of the Sea, known as ICES, assesses all eastern Atlantic stocks and publishes annual Total Allowable Catch recommendations. All seven stocks it assessed in recent years are considered to be harvested sustainably.

  In the western Atlantic, the eastern Georges Bank stock is jointly assessed by Canada and the United States. The Canada-United States Transboundary Management Guidance Committee, established in 2000, coordinates that management.

  Haddock currently sits on the Greenpeace seafood red list because of concerns about bottom trawling's impact on the marine environment. The Monterey Bay Aquarium classifies it as a "good alternative". Many fisheries hold Marine Stewardship Council certification for sustainability. The tension between those assessments reflects a genuine debate about method, not stock size: the fish populations in both the eastern and western Atlantic are considered to be harvested sustainably by the bodies that assess them.

• 7. Smoke, Tradition, and the Table

  ›

  Smoked haddock has its own geography. Finnan haddie takes its name from Finnan, also known as Findon, a fishing village in Scotland where the fish was originally cold-smoked over smouldering peat. It is traditionally poached in milk and served for breakfast.

  Arbroath, on the east coast of Scotland, produces a different product entirely. The Arbroath smokie is hot-smoked and requires no further cooking before eating. These two Scottish traditions represent distinct techniques applied to the same fish.

  In Grimsby, the smoking of haddock became a craft refined over generations. Traditional Grimsby smoked fish is produced in family-run smokehouses, with Grimsby fish market sourcing its haddock from Iceland, Norway, and the Faroe Islands. Other long-boneless varieties are smoked in oak chips with the skin left on the fillet.

  Fresh haddock also has a clear place at the table. Along with Atlantic cod and plaice, it is one of the most popular fish in British fish and chips. In Scotland it is the dominant choice for a fish supper. Young, small haddock and cod are sold as scrod in Boston, Massachusetts, a term that refers to the size of the fish rather than the species. In Norway, haddock is the main ingredient in fiskeboller, or fishballs. Unlike cod, haddock does not salt well, which is why drying and smoking became the primary preservation methods for the species.