in the clear waters of the upper basins, young salmon grow up in their
birthplace during a period which spans from 1 to 3 years on the Allier.
On the last spring of this period, they undergo a phenomenon, «
smoltification », which will turn them, freshwater fish, into
saltwater fish. Juveniles, now called « smolts », go down
the river to the Atlantic to their feeding grounds. They stay off
the coasts of Greenland and the Feroe Islands 1 to 4 summers, feeding
on shrimps and little fish, gaining 4 to 6 pounds (2 to 3 kilos) a
year. Then, moved by their breeding instinct which lead them back
without fail to their native river, they begin their 4,000-mile long
- 600 miles upstream the river - (6,000 km overall, 900 km upstream
the river) journey back.
As they enter the river, salmon stop feeding and must use up their
organismís reserves to go up the river, over no less than 20 important
obstacles (sills, dams...), and elaborate their genital products.
Nowadays, salmon need more than 6 months to reach their spawning grounds;
it used to be 2 months when the river was not artificialized yet.
When they enter the Loire mouth, Atlantic salmon are a slender silver
fish, with a shining metal-like coat. Their size and weight vary greatly,
according to the number of years they spent at sea: generally, they
weigh between 10 and 20 pounds (5 to 10 kilos) and are 28 to 36 inch-long
(70 to 90 cm-long). When they reach the spawning grounds where they
were born to finally breed, they are worn-out and wasted by a fast
which has been lasting for 6 to 14 months according to the date
they entered the estuary; they weigh no more than half or two thirds
of their original weight.
Salmon bécard - Photo CSP
The life cycle
1- After 1 to 3 years spent at
sea, adult salmon enter the river. This happens all year round
at different periods according
to the age of the salmon and weather conditions. Activity peaks:
April for big salmon which spent 1 to 3 years
at sea, June-July for salmon which spent 1 year at sea
2 - Salmon go back to their breeding
area, go over obstacles while sexually maturing
3 - Secondary sexual characteristics
appear: for the male, the coat takes on a reddish hue and a
6 - The female digs up its spawning
ground in a shallow gravel area where current is swift.
7 - In November and December,
the female lay its eggs which are fecundated by the male.
8 - The eggs are buried under
the spawning groundís gravel.
9 - The embryo develops safely
in the spawning ground.
10 - The alevin comes out of the
spawning ground in February or March and lives in neighboring
11 - 1 or 2 year-old salmon
12 - Smolt ready to go back to
13 - Smolts go back to sea in
the spring after 1 or 2 years spent in the river.
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