Kathleen Nelligan, age 13, Of Louisville, Ky., for her question:

How often do salmon migrate?

The pink salmon of the Pacific Ocean always migrates back to its breeding ground when it is two years old. But other species of salmon are not so definite. Some of the Atlantic salmon travel 1500 miles from land and do not migrate until they are five years old. Others of the some species migrate after one, two or three years.

The rich sockeye salmon of the Pacific is also indefinite about the time it returns to its breeding grounds. Most of them return after four or five years of ocean life. Some return after three year's, and same of the whopping six pounders have been in the ocean for eight years.