The salmon (Salmo salar) is a fish of the Salmonidae family. Salmon are hatched in fresh water, and make for the sea, where most of their food is found, usually in their third year. When first hatched the infant salmon are known by the name of 'alevin'. They soon attain the 'parr' stage, being then olive-brown in colour with dark transverse bands and red spots. When two years old the silvery 'smelt' stage is attained.
Salmon generally re-enter the river to spawn for the first time when some three and a half years old during the autumn months, when they are known as ' Grilse'. On the way up-stream the fishfeed scarcely at all, and so lose much in condition. Often the journey is arduous, necessitating the leaping of falls and other obstacles. At this time the fish lose their silvery tint, and the males are known as 'red fish', the females as 'black fish'. Savage fights may take place between the males, and their jaws undergo a strange modification, often assuming a hooked or beak-like form. Having reached the gravely shallows suitable for spawning, trough-shaped depressions known as 'redds' are excavated by the fish with their tails, and in these the hen- fish deposit their eggs, loosely covering them with silt. It is at this period that many eggs become fertilised by trout, which seize the opportunity to do so when the cock salmon is otherwise engaged repulsing rivals of his own species. It is doubtful if salmon spawn more than three or four times, as the procedure is very exhaustive, and an interval of some years may elapse between successive spawnings. In the River Tay in Scotland the salmon attains a weight of over eighty pounds. Research Salmon
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Nature
Research Salmon