Identifying characteristics: (Non-Native Fish) Two dorsal fins including one adipose fin, dark mouth and gums, large oval black spots on tail and back (lake-run mostly silver), 13-17 rays in anal fins.

Known in its native Pacific Northwest as the humpback salmon, this Pacific salmon was unintentionally introduced into the Great Lakes in the mid 1950s. The population has maintained itself since then, slowly growing in numbers and spreading to much of Lake Superior and Lakes Huron and Michigan.

Pink salmon spawning runs begin in the summer in the Great Lakes. Females hollow out a nest in the gravel of a streambed by lying on one side and beating vigorously with their tails to remove silt and light gravel. The result is a deep trough with a raised rim of gravel at the downstream edge. Once they are fertilized, the eggs are covered. The female guards the nest as long as possible, but dies within a few days or weeks.

Depending on water temperatures, eggs hatch from late December to late February, and the young remain in the gravel nest until late April or early May. Once they are mature enough to leave the nest, they journey downstream in large schools. After about 18 months in the lake the young pinks have reached adulthood and will begin their spawning cycle.

Adult size for pink salmon is two to seven pounds and 17 to 19 inches in length. The average life span is two years, although some pink salmon have been known to live for three years. Great Lakes pink salmon eat a variety of fish and other aquatic animals. Young pinks, still in the stream, fall prey to trout, coho salmon, smelt, other predacious fish, fish-eating birds and some mammals.