Mark Habecker, age 11, of Washington Boro, Pa., for his question:
HOW DO SALMON REPRODUCE?
Probably no more interesting fish exists than the salmon. Its dual life, first as a freshwater fish, then as an adult in the salty waters of the oceans who comes back to freshwater streams to spawn, makes it intriguing enough. Even more fascinating is the fact that it finds its way back to the same spawning grounds where it started life as a tiny egg. And it must do this in the face of such overwhelming obstacles as time, distance and waning strength.
A salmon begins his life as a wee egg, a small red ball no larger than a buckshot, deposited in the gravelly bottom of a swift flowing stream. In time the egg hatches into a tiny fish, still carrying the yolk sac that will feed him for days to come. At this stage he is called a fry, and he may spend from two to three months hiding in the nest his mother scooped out with her tail.
When the fry has exhausted the food supply in the yolk sac, he pushes his way up and out of the gravel and begins to look for food on his own. If the tiny fingerling, as he is now called, knew what was in store for him, he might well just stay where he began life, but such is not the case. If he is lucky he might live for eight to nine years. However, hungry trout, bass, numerous birds and even larger predators such as bears are just waiting to cut his life short.
The fingerling may spend as long as one or two years swimming around the gravel beds where it was hatched. Then one day an inexplicable urge causes him, and all other salmon his age, to begin swimming downstream toward the sea. At this stage, he is called a smolt, and the dangers he has faced in the past are only a prelude to present hazards. He must pass over rapids and waterfalls and elude countless predators before he reaches the relative security of the mighty ocean.
A female salmon may lay from 4,000 to 27,000 eggs, depending on which salmon expert you care to believe. Of the eggs laid, only about half are fertilized, and it is still only a small percentage of these that survive to the smolt stage. And those that do face a great number of predators in the ocean.
Salmon that reach the ocean may spend up to five years there. Then, the same urge that led them to the ocean leads them back, through countless underwater miles, to the mouth of their home streams. After reaching fresh water, they stop eating and live off fat stored in their body. Displaying a seemingly inexhaustible supply of energy, they fight their way upstream, over rapids and falls. At .long last they reach their destination the place of their birth. Here the female scoops a hole in the gravel with her tail and deposits her eggs, which are promptly fertilized by the male.
It is estimated that only one in 20 salmon lives to return to its spawning ground. The natural predators account for only a small percentage of casualties. Man is the real predator, and if things continue the salmon is in danger of extinction.