Haddock
Haddock are a bottom-dwelling member of the cod family found across the North Sea, around the Scottish coast, and into northern and western waters. In the UK they're primarily a boat angler's fish, caught from charter and private vessels over deep ground.
They're also one of the country's most commercially important species — the fish in most fish-and-chip shops and the base of smoked classics like Finnan Haddie and Arbroath Smokie.
Scientific Name: Melanogrammus aeglefinus
Also known as Finnan Haddie, Haddie
- Silver-grey flanks with a distinctive black 'Devil's Thumbprint' — a dark blotch just above and behind the pectoral fin — makes haddock hard to confuse with cod or pollock.
- The lateral line runs dark (almost black) along the side, and the first dorsal fin is sharply pointed rather than rounded as in Atlantic cod.
- Most rod-caught fish run 1–3 lb, with fish over 5 lb considered a good catch; the species can reach 40 lb but fish that size are exceptionally rare from rod and line.
- Three dorsal fins and two anal fins, slender tapering body, small chin barbel — typical cod-family build but noticeably slimmer than cod.
What to know
Habitat Distribution
- Native to UK waters; the main rod-and-line fishery sits in the North Sea, particularly the northern and central areas where the Scottish fleet operates, and around the Scottish coast generally.
- Also present in Cornish and south-west waters (ICES divisions VIIe–h), though stocks there are under pressure and catches are lower than in northern grounds.
- A demersal, schooling species — lives and feeds near the seabed in depths of roughly 50–200 m, occasionally shallower, never entering brackish or estuarine water.
- Prefers cold water and hard, gravelly or mixed-bottom ground; found over rock, gravel, sand and mud depending on season and food availability.
Key Locations
- North and central North Sea — the main Scottish commercial and charter-boat grounds, with the strongest stocks and most consistent rod fishing.
- Scottish west coast and Minches — accessible from ports like Ullapool and Oban; mixed-ground boat fishing over rocky marks.
- Cornish south-west waters — haddock are present and landed commercially at Cornish ports, though stocks here are under more pressure than in northern grounds.
- Northern Isles (Orkney and Shetland) — deep, cold water close to shore makes these some of the most productive haddock grounds accessible to charter boats.
Specific Spots
- Rocky and mixed rough ground holds haddock well — they forage along the seabed edge where hard bottom meets sand, picking off worms, shellfish and small fish.
- Wrecks and reef edges concentrate fish, especially where tidal flow creates a current break that pushes food along the bottom.
- Sandy depressions between reef patches are worth working — haddock move onto softer ground to dig out sand eels, worms and brittlestars.
- In deeper water (100 m+), marks where the bottom rises sharply — pinnacles, banks — tend to aggregate feeding fish, particularly on the flood tide.
Haddock FAQ
Answers from onWater's species guide.
What are the best lures and bait for Haddock?
Fresh lugworm, ragworm, squid strip and mackerel flank are the go-to baits; cocktail baits, worm tipped with a sliver of squid, are a reliable combination that adds scent and movement.
When is the best time to fish for Haddock?
Late summer through autumn (August–November) is generally the most productive period for rod-and-line fishing, with fish in good condition after spawning. Winter fishing (December–February) can produce well in northern waters when weather allows boat access, and fish are often concentrated on deeper marks.
How do you catch Haddock?
Haddock in UK waters are almost exclusively a boat-fishing target, worked from charter or private vessels over known bottom marks using baited paternoster rigs fished hard on the seabed.
What do Haddock eat?
Haddock feed mainly on bottom-dwelling invertebrates, marine worms, brittlestars, small crabs, shellfish and sea urchins, which is why baited rigs fished hard on the deck consistently outfish lures.
Where do Haddock live?
Native to UK waters; the main rod-and-line fishery sits in the North Sea, particularly the northern and central areas where the Scottish fleet operates, and around the Scottish coast generally.
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