Fish
Pink Salmon
Oncorhynchus gorbuscha · also called humpback salmon, humpies
Every other year, without fail, a particular river’s pink salmon population returns to spawn, while the same river’s opposite-year class continues its own separate two-year cycle almost entirely apart, two genetically distinct populations sharing one river but rarely mixing.
Overview
The pink salmon, Oncorhynchus gorbuscha, is the smallest yet most abundant Pacific salmon species, native to the North Pacific Ocean and connected river systems across North America and Asia. Its rigid two-year life cycle and dramatic spawning-season hump set it apart from its larger, less numerous salmon relatives.
Small fish, enormous numbers
What the pink salmon lacks in individual size, it makes up for in sheer population numbers, its predictable two-year cycle producing some of the largest salmon runs anywhere in the North Pacific during peak spawning years.
Status
Least Concern — widespread and abundant across much of the North Pacific and connected river systems, supporting significant commercial fisheries.
Pink Salmon: common questions
Why do pink salmon only return in either even or odd years?
A pink salmon follows an extremely fixed two-year life cycle, meaning individual populations spawning in a given river typically return only in either even-numbered or odd-numbered years, with fish from the two-year classes remaining largely genetically distinct from one another despite sharing the same spawning rivers.
Why is it called the humpback salmon?
A male pink salmon develops a pronounced hump on its back during the spawning migration, a dramatic physical change that gives the species its common alternate name, humpback salmon, distinguishing spawning males quite visibly from their smoother-bodied appearance while at sea.
Is the pink salmon really the most common Pacific salmon?
Yes, despite being the smallest Pacific salmon species by individual size, the pink salmon is generally considered the most abundant Pacific salmon by overall population numbers across its range, making it a particularly important species for both commercial fisheries and the broader North Pacific food web.
Where does the pink salmon live?
The pink salmon is native to the North Pacific Ocean and connected river systems across North America and Asia, spawning in rivers from the Pacific Northwest through Alaska and across to eastern Russia and Japan, following its characteristic two-year life cycle throughout this range.