Stephen Kopchicks age 10 of Bridgeport Conn. for his question:
Why do salmon die when they spawn?
The life story of an animal often reflects the long history of its ancestors. This may be why an insect goes through a chrysalis stage. In the dim past, its ancestors may have had to sleep through long stages of drought and food shortage. The ancestors of the handsome salmon overcame food shortages by going to sea. But for some reason the baby salmon never learned to cope with salt water.
The babies are born in the rippling fresh water streams far from the sea. They hatch from eggs and spend from one to three years in fresh water. The little fellows feed on crustaceans and gradually make their way down stream. At last they join the ocean of salty water and feed on marine shellfish and crustaceans. Food is now more plentiful and the handsome fish grow fat and strong.
As a rule, the salmon lives most of his life in the ocean. He may travel 1500 miles out to sea. He is now a salt water fish used to salt water food. For three to eight years he enjoys this sea going life. Then he remembers that fresh water stream, where he was born. The strong voice of Mother Nature reminds him that he has an important job to do. He must hand on life to a new generation of salmon.
Somehow he knows that food will be short. So he eats a lot and takes on a supply of fat. He starts the long Journey homes swimming 45 to 60 miles a day. In some mysterious way he finds the very river he left. Once in the fresh water, he eats no more. Perhaps he can no longer eat fresh water food.
The Journey upstream may be 2000 miles. He swims against the current and leaps rapids and waterfalls. All this time he lives on his fat. At last he reaches the same gravelly cradle in which he was born. Other salmon are there with him. He chooses a wife and fights off his rivals.
Mrs. Salmon digs the nest. She lies on her side and flicks her tail to make a hollow in the gravel. Both parents defend the eggs. Mama goes a few feet upstream and shovels a pile of gravel over them. The parents may build several of these nests, each is a cradle of buried eggs.
All this hard work and the parent salmon may have been without food for a whole year. The journey back to sea and salt water food is long, too long. The Red salmon, the big Chinock and most other salmon are too tired to make it. So they die, right there beside the cradle where they were born. They have lived their lives, mostly in the sea, and they succeeded in the most important job of all. They handed on life.
The European salmon does not always die after spawning. The rivers are shorter and the long journey home is not so far. He may make two, even three trips back to spawn. The Pacific salmon always dies after spawning, even when he lives all his life in fresh water. This salmon repeats and repeats the life story of his ancestors.