Salmon can be found in freshwater streams and oceans. An alevin, which is the young of a salmon, commonly feeds on caddisflies, mayflies and stoneflies. Examples of the preys of an adult salmon are herrings, crustaceans, sand launces and mackerels. The scale of a salmon contains rings that tells the age of the salmon. An alevin hatches at freshwater streams. When it has grown into an adult, it will enter the ocean. When an adult wants to spawn eggs, it will return to the freshwater streams again. The life span of a salmon is about 8 years. Some of the freshwater predators of a salmon are kingfishers, otters and ospreys. Some of the saltwater predators are gulls, cods, seals and sharks. A female salmon needs to spawn about 3000 - 15000 eggs because a lot of organisms like to eat salmon's eggs. Usually, only few eggs will hatch into an alevin. After the female salmon spawn its eggs, it will abandon its eggs. That is why it is easier for its predators to eat them.
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*Informations from:-
> http://www.k12.nf.ca/she/pgreen/Page/index.html
> http://en.wikipedia.org/wiki/Spawn_(biology)
> http://en.wikipedia.org/wiki/Atlantic_salmon#Life_stages
> http://library.thinkquest.org/C0124402/data/html/2/2reproduction.htm
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