A haddock is a type of saltwater fish that lives in the cold waters of the North Atlantic Ocean, especially near Iceland, Norway, and the northeastern coast of North America. Haddock look similar to their close relative, the cod, but they're usually smaller and have a distinctive dark spot behind their gills called the “thumbprint” or “Devil's mark.”

For centuries, haddock has been one of the most important fish in the North Atlantic fishing industry. Fishers catch haddock using large nets called trawls that drag along the ocean floor. The fish feeds on small creatures like worms, shellfish, and other bottom-dwelling animals.

People prize haddock for its mild, slightly sweet flavor and firm white flesh. In Britain, fish and chips is traditionally made with haddock. The fish is also commonly smoked to make finnan haddie, a Scottish breakfast dish. Because haddock doesn't have a strong fishy taste, many people who think they don't like seafood find they actually enjoy it.

Like many ocean fish, haddock populations have faced challenges from overfishing, but fishing regulations and careful management have helped haddock numbers recover in recent decades.