Pink Salmon

Pink Salmon is the smallest and generally most abundant of the Pacific salmon species, distinguished by an unusually rigid two-year life cycle that leads to genetically distinct odd-year and even-year populations in many rivers. Native to coastal drainages from northern California to Alaska and across to Russia and Japan, Pink Salmon typically use shorter coastal rivers and migrate to the ocean almost immediately after hatching, unlike other salmon species that rear in freshwater for extended periods. The species gets its 'humpback' nickname from the pronounced dorsal hump that spawning males develop, a feature more exaggerated than in any other Pacific salmon.

Key field marks:

• Large, oval black spots on the back and on both lobes of the tail fin, larger and more numerous than in other salmon
• Small, streamlined body size, generally the smallest Pacific salmon species
• Silvery sides with a blue-green back in ocean phase
• Spawning males develop a dramatic, exaggerated hump behind the head and a strongly hooked jaw
• Very small scales compared to other Pacific salmon

Look-alikes: The prominent hump and large oval tail spots readily distinguish spawning males from other salmon; ocean-phase fish can be confused with Chum Salmon but Pink Salmon have larger, more distinct tail spotting.

Pink Salmon range widely across the North Pacific, spawning in coastal rivers and streams from northern California and Washington north through British Columbia and Alaska, and across to Siberia, the Russian Far East, and northern Japan. They favor shorter coastal drainages close to the sea, since fry migrate to saltwater almost immediately after emerging from gravel, rather than rearing in freshwater for extended periods like other salmon. Spawning occurs in the lower and middle reaches of rivers, often close to tidewater, in gravel beds with moderate current. The species has a fixed two-year lifespan, so a given river typically shows strong runs in either odd or even years, with the other year comparatively weak.

Pink Salmon have the shortest and most rigid life cycle of any Pacific salmon, living almost exactly two years from hatching to spawning and death. Fry migrate to the ocean almost immediately after emergence, spending little to no time rearing in freshwater compared to other salmon species, then grow rapidly at sea feeding on zooplankton, small fish, and crustaceans. Returning adults undertake relatively short spawning migrations back to coastal rivers, where males develop their characteristic humped back and compete aggressively for spawning access to females. Because of the fixed two-year cycle, populations in a given river are genetically separated into distinct odd- and even-year lineages that rarely interbreed.