Telling them apart
Haddock vs Pollock
Look for the thumbprint. A haddock carries a dark blotch on the shoulder above the pectoral fin and a black lateral line. A pollock has neither, and its lower jaw projects past the upper.
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Side by side
| What to look at | Haddock | Pollock |
|---|---|---|
| Scientific name | Melanogrammus aeglefinus | Pollachius virens |
| Shoulder | A dark thumbprint blotch | Plain |
| Lateral line | Black | Dark, nearly straight, no blotch above it |
| Lower jaw | Does not project | Projects past the upper |
| First dorsal fin | Tall and sharply pointed | Lower and more rounded |
| Where in the column | On gravel and pebble bottom | Well up off the bottom |
| Flesh | White, fine and delicate | Greyer and coarser |
Why the difference matters
Both come over the rail on the same New England trip under different rules, and haddock in particular carry a minimum size that pollock often do not. The thumbprint is the fastest check and stays visible on a dead fish long after the colour has drained.
Size limits, bag limits, slot limits and seasons are set by your state wildlife agency — and for many offshore and migratory species by federal regulators — and on many waters they differ from the statewide rule. They also change between seasons. Check the current regulations for the exact water you are fishing before you keep a fish — we do not republish limits here, because a number that is a season out of date is worse than no number.
Full entries
Each fish has its own page with every field mark, the rest of its look-alikes, where it holds and the conditions it feeds in: Haddock and Pollock.
Or skip the key entirely — photograph the fish and Global Fishing League names the species, returns the scientific name with it, and files the catch with the tide, pressure, water temperature and everything else it came from.