The haddock exhibits a characteristic body shape commonly seen in cod family members. It boasts an elongated, tapering body with a small mouth that doesn't extend below the eye. The snout showcases a wedge-shaped profile, with the upper jaw protruding more than the lower jaw. A notable feature is the small barbel present on the chin. Distinguished by its dark grey-brown to nearly black upper side, the haddock's lower body displays a dull silvery white coloration. The black lateral line, curving slightly over the pectoral fins, provides a striking contrast against the whitish background. One peculiar marking is the oval black blotch, often referred to as the "Devil's thumbprint," positioned between the lateral line and the pectoral fin. This unique feature lends the fish its scientific name, Melanogrammus, derived from the Greek words for "black" and "letter/signal."
The haddock possesses three dorsal fins, with the first being triangular in shape. Each dorsal fin has a specific number of fin rays, ranging from 14 to 17 in the first, 20 to 24 in the second, and 19 to 22 in the third. Additionally, there are two anal fins, each consisting of 21 to 25 and 20 to 24 fin rays, respectively. Notably, all the dorsal and anal fins remain separate from one another. The pelvic fins are relatively small, featuring an elongated first fin ray. Occasionally, variations occur, showcasing different colors, such as barred patterns, golden shades on the back, or a lack of the dark shoulder blotch.
The haddock can be found in the North Atlantic Ocean and its associated seas. While populations exist on both sides of the Atlantic, the species is more abundant in the eastern Atlantic. In this region, the haddock's range stretches from the Bay of Biscay to Spitzbergen, with its highest abundance observed north of the English Channel. It also occurs in the Arctic, around Novaya Zemlya and the Barents Sea. Notably, the largest stocks are found in the North Sea, off the Faroe Islands, Iceland, and the Norwegian coast. While haddock can be found off the western Greenland and Cape Hatteras in North America, the main commercially fished stock resides between Cape Cod and the Grand Banks.
As a demersal species, the haddock prefers depths ranging from 10 to 450 meters, although it is most commonly found between 80 and 200 meters. Its habitat consists of substrates composed of rock, sand, gravel, or shells. The haddock thrives in temperatures ranging from 4 to 10 degrees Celsius (39 to 50 degrees Fahrenheit). The species exhibits different migratory behaviors based on location. In regions like Iceland and the Barents Sea, extensive migrations occur, while movements in the northwestern Atlantic are more limited, primarily associated with spawning activities. Maturity is reached at around 4 years for males and 5 years for females, with some regional variations. Notably, the sex ratio of haddock is relatively balanced, although females tend to predominate in shallower areas, while males show a preference for offshore waters.
Spawning takes place at depths ranging from 50 to 150 meters. In the northwestern Atlantic, the spawning season lasts from January to July, with some variations in different areas. In the northeastern Atlantic, the peak of spawning occurs between February and June, with March and April representing the highest activity periods. Haddock eggs are pelagic, with a diameter of 1.2 to 1.7 millimeters. The hatching process takes approximately one to three weeks. After metamorphosis, the larvae remain pelagic until they reach a length of around 7 centimeters, at which point they settle into a demersal lifestyle. Growth rates vary across regions, with haddock reaching sizes of 17 to 19 centimeters at one year old, 25 to 36 centimeters at two years old, and up to 75 to 82 centimeters at 13 years old. The average lifespan of haddock is approximately 14 years.
During their larval stages, haddock predominantly feed on the immature forms of copepods, as well as pelagic post-larvae measuring 3 to 10 centimeters. As they progress to the settled, demersal post-larval stage, their diet shifts to include benthic invertebrates, while still incorporating pelagic organisms like krill. Sand eels, Trisopterus esmarkii, American plaice, gobies, European sprat, Atlantic herring, capelin, silver hake, American eels, and argentines are among the fish species that serve as prey for adult haddock. In addition to fish, shellfish, sea urchins, brittlestars, and worms form vital components of their diet, especially during the winter season. Haddock often exhibit shoaling behavior when feeding, as indicated by the similarity in stomach contents among multiple individuals caught simultaneously. Juvenile haddock play a significant ecological role as prey for larger demersal fish, including other gadoids, while seals target larger haddock for sustenance.
In conclusion, the haddock, Melanogrammus aeglefinus, stands as a remarkable saltwater fish belonging to the family Gadidae. With its distinct body shape, coloration, and unique markings, the haddock captures the attention of both fish enthusiasts and culinary experts. Thriving in the North Atlantic, this species boasts significant populations in the eastern Atlantic, particularly the North Sea, Faroe Islands, Iceland, and the Norwegian coast. Its habitat preferences, migration patterns, and feeding habits further contribute to the species' ecological significance. By delving into the intricate details of the haddock's description, distribution, habitat, biology, and feeding habits, we hope to provide a comprehensive resource that helps you explore the captivating world of this fascinating fish.