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Haddock: the story on HearLore | HearLore
Haddock
The haddock carries a secret mark on its side that has fooled fishermen and scientists for centuries, a dark oval blotch known as the Devil's thumbprint. This distinctive black spot, located between the lateral line and the pectoral fin, is the defining feature that separates the haddock from its cousin, the Atlantic cod. The very name of the genus, Melanogrammus, derives from the Greek words for black and letter, a direct reference to this unique signal on the fish's flank. While the upper body ranges from dark grey-brown to nearly black, the lower belly remains a dull silvery white, creating a striking contrast that helps the fish blend into the ocean depths. The fish possesses a wedge-shaped snout with a small mouth that does not extend below the eye, and a tiny barbel on the chin that aids in sensing prey on the ocean floor. These physical traits, combined with three distinct dorsal fins and two anal fins, make the haddock a master of camouflage in the North Atlantic, where it thrives as the sole species in its monotypic genus.
Waters of the North Atlantic
Populations of haddock stretch across the North Atlantic Ocean, yet they exist as isolated communities with little interchange between them. The largest stocks reside in the North Sea, off the Faroe Islands, around Iceland, and along the coast of Norway, while a separate population extends from western Greenland down to Cape Hatteras off the coast of North America. In the north-east Atlantic, the fish is most abundant north of the English Channel, ranging as far north as Spitzbergen and the Barents Sea. Conversely, the North American stock is concentrated from Cape Cod to the Grand Banks of Newfoundland. These populations are demersal, meaning they live near the bottom of the sea, typically at depths between 50 and 200 meters, though they can be found as deep as 500 meters. The fish prefers substrates made of rock, sand, gravel, or shells, and maintains a preference for water temperatures between 4 and 10 degrees Celsius. While haddock in the north-western Atlantic make restricted movements to and from spawning areas, those in the Barents Sea and off Iceland undergo extensive migrations, covering vast distances to find suitable conditions.
Life Cycle and Growth
A haddock reaches sexual maturity at 4 years old in males and 5 years old in females, though the population in the North Sea matures much faster, with males reaching maturity at 2 years and females at 3 years. The reproductive capacity of the female varies dramatically with size, as a fish measuring 30 centimeters bears 55,000 eggs, while a larger specimen at 50 centimeters produces 1,841,000 eggs. Spawning occurs from depths of around 100 meters, with the season running from January to July in the north-western Atlantic and from February to June in the north-eastern Atlantic, peaking in March and April. The eggs are pelagic, floating in the water column with a diameter of 1.5 millimeters, and take one to three weeks to hatch. Once hatched, the larvae remain pelagic until they grow to about 3 centimeters, at which point they settle to the bottom to begin their demersal life. The lifespan of the fish is approximately 14 years, with the longest recorded individual reaching 70 centimeters in length and weighing 4.5 kilograms, though the vast majority caught in the United Kingdom measure between 30 and 50 centimeters. Growth rates have fluctuated significantly over the last four decades, showing rapid increases in the early 2000s before slowing again, possibly due to an exceptionally large year class in 2003.
What is the defining physical feature of the haddock that distinguishes it from the Atlantic cod?
The haddock is distinguished by a dark oval black spot known as the Devil's thumbprint located between the lateral line and the pectoral fin. This unique signal on the fish's flank is the defining feature that separates the haddock from its cousin the Atlantic cod. The genus name Melanogrammus derives from Greek words for black and letter referencing this specific mark.
Where do haddock populations live and what depth do they prefer in the North Atlantic?
Haddock populations stretch across the North Atlantic Ocean with the largest stocks residing in the North Sea off the Faroe Islands around Iceland and along the coast of Norway. These demersal fish live near the bottom of the sea typically at depths between 50 and 200 meters though they can be found as deep as 500 meters. They prefer substrates made of rock sand gravel or shells and maintain a preference for water temperatures between 4 and 10 degrees Celsius.
How long does a haddock live and when does it reach sexual maturity?
The lifespan of the haddock is approximately 14 years with the longest recorded individual reaching 70 centimeters in length and weighing 4.5 kilograms. A haddock reaches sexual maturity at 4 years old in males and 5 years old in females though the population in the North Sea matures much faster with males reaching maturity at 2 years and females at 3 years.
What is the history of haddock population productivity known as the gadoid outburst?
The history of haddock populations is marked by periods of extraordinary productivity known as the gadoid outburst which occurred from the 1960s up to the early 1980s. Notable peaks in productivity occurred in 1962 and 1967 with lesser increases in 1974 and 1999. These revivals did not have a lasting effect on the population due to high fishing mortality which prevented the stocks from recovering to historical levels.
How is haddock smoked and what are the traditional varieties from Scotland?
The smoking of haddock reached a level of refinement in the English town of Grimsby where traditional smokehouses have been family-run businesses for generations. One of the most popular forms is Finnan haddie named after the fishing village of Finnan or Findon in Scotland where the fish was originally cold-smoked over smouldering peat. Another smoked version the Arbroath smokie is produced in the town of Arbroath on the east coast of Scotland and is a hot-smoked haddock that requires no further cooking before eating.
How is haddock fished and what are the main fishing grounds in the eastern Atlantic?
Haddock is fished year-round using gear such as Danish seine nets trawlers long lines and gill nets often caught in mixed species fisheries with other groundfish like cod and whiting. The main fishing grounds in the eastern Atlantic are in the Barents Sea around Iceland around the Faeroe Islands in the North Sea the Celtic Sea and the English Channel. Landings in the eastern Atlantic have fluctuated around 200 to 350 thousand tonnes in the period from 1980 to 2017.
In their larval stages, haddock feed primarily on the immature stages of copepods, ostracods, and limacina, but their diet shifts as they grow to include larger pelagic prey such as amphipods, euphausiids, and the eggs of invertebrates. Once they settle to the bottom, they gradually switch to benthic prey, with adults primarily consuming sea urchins, brittlestars, bivalves, and worms. They will also feed opportunistically on smaller fish like capelin, sandeels, and Norway pout. Juvenile haddock serve as an important food source for larger demersal fish, including other gadoids, while seals prey on the larger fish. The ecosystem surrounding the haddock is complex, with the fish playing a critical role in the food web of the North Atlantic. Despite their importance, the haddock faces threats from parasites, including the cod worm, Lernaeocera branchialis, which starts life as a free-swimming crustacean larva before attaching to flatfish or lumpsuckers. The female worm then finds a haddock, penetrates its gills, and roots itself in the rear bulb of the host's heart, extracting nutrients from the circulatory system while releasing new generations of offspring into the water.
The Gadoid Outburst
The history of haddock populations is marked by periods of extraordinary productivity known as the gadoid outburst, which occurred from the 1960s up to the early 1980s. This phenomenon resulted in above-average recruitment similar to that of Atlantic cod and whiting, leading to a more southerly distribution of the fish and a strong effect on the biomass of the spawning stock. Notable peaks in productivity occurred in 1962 and 1967, with lesser increases in 1974 and 1999. However, these revivals did not have a lasting effect on the population due to high fishing mortality, which prevented the stocks from recovering to historical levels. In 1999, there was strong recruitment, but since then, the recruitment rate has been very low. The growth rates of haddock have also undergone significant changes, with fish attaining adult size much earlier than was noted 30 to 40 years ago, though the degree to which these larger, younger fish contribute to reproductive success remains unknown. The overall sex ratio is roughly 1:1, but in shallower areas, females predominate, while males show a preference for waters further offshore.
The Grimsby Smokehouse
The smoking of haddock reached a level of refinement in the English town of Grimsby, where traditional smokehouses have been family-run businesses for generations. Grimsby fish market sources its haddock from the North East Atlantic, principally from Iceland, Norway, and the Faroe Islands, regions that have not seen the large-scale depreciation in fish stocks seen in EU waters. One of the most popular forms of haddock is Finnan haddie, named after the fishing village of Finnan or Findon in Scotland, where the fish was originally cold-smoked over smouldering peat. This variety is often poached in milk and served for breakfast, while another smoked version, the Arbroath smokie, is produced in the town of Arbroath on the east coast of Scotland. The Arbroath smokie is a hot-smoked haddock that requires no further cooking before eating. Smoked haddock is naturally an off-white color but is frequently dyed yellow, as are other smoked fish, to enhance its visual appeal. These smoked varieties are essential ingredients in dishes like kedgeree, an Anglo-Indian meal, and Cullen skink, a chowder-like soup from Scotland.
Fisheries and Management
Haddock is fished year-round using gear such as Danish seine nets, trawlers, long lines, and gill nets, often caught in mixed species fisheries with other groundfish like cod and whiting. The main fishing grounds in the eastern Atlantic are in the Barents Sea, around Iceland, around the Faeroe Islands, in the North Sea, the Celtic Sea, and the English Channel. Landings in the eastern Atlantic have fluctuated around 200 to 350 thousand tonnes in the period from 1980 to 2017. During the 1980s, the largest portion of the catch was taken at Rockall, but from about 2000, the majority of the catch is caught in the Barents Sea. All stocks in the eastern Atlantic are assessed by the International Council for the Exploration of the Sea, which publishes recommendations on an annual basis for Total Allowable Catch. In the western Atlantic, the eastern Georges Bank haddock stock is jointly assessed by Canada and the United States, and the stock is collaboratively managed through the Canada, United States Transboundary Management Guidance Committee, established in 2000. The commercial catch of haddock in North America was approximately 40 to 60 thousand tonnes per year between 1920 and 1960, but this declined sharply in the late 1960s to between 5 and 30 thousand tonnes per year.