### Identification The Alaska Pollock (*Gadus chalcogrammus*) is a sleek, torpedo-shaped member of the cod family, typically reaching 12 to 20 inches in length. To identify one in the field, look for its signature triplet of dorsal fins and two anal fins—a classic gadid trait. Unlike the Pacific Cod, which has a prominent chin barbel and an overhanging upper jaw, the Pollock possesses a protruding lower jaw and a barbel so tiny it is often invisible. Its coloration is a striking, mottled olive-green or brown on the back, transitioning into shimmering silver sides and a white belly, often punctuated by dark, irregular speckles.
### Habitat & Range These are the silver ghosts of the North Pacific. Their range is vast, stretching from the Sea of Japan, through the icy Bering Sea, and down the coast to Central California. They are primarily semi-pelagic, meaning they split their time between the open water column and the seafloor. You’ll typically find them hovering over the continental shelf and slope at depths of 100 to 300 meters, though they have been recorded as deep as 1,000 meters.
### Behaviour Pollock are highly gregarious, forming gargantuan schools that can extend for miles. They are famous for their "diel vertical migration": as the sun sets, these massive clouds of fish rise toward the surface to feed under the cloak of darkness, retreating to the safety of the shadowy depths at dawn. During the spring spawning season, they congregate in dense "spawning balls" where females can release up to 15 million eggs over several weeks.
### Diet They are opportunistic, mid-water hunters. As juveniles, they focus almost exclusively on zooplankton and krill (euphausiids). As they mature, their diet expands to include small crustaceans and fish. Interestingly, adult Pollock are known to be quite cannibalistic, frequently snacking on younger members of their own species when other food sources are scarce.
### Fascinating Fact The Alaska Pollock supports the largest single-species food fishery in the world, yet it is a "hidden" giant. If you have ever eaten a fast-food fish sandwich, a fish stick, or "imitation crab" (surimi), you have almost certainly eaten *Gadus chalcogrammus* without even knowing its name!