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High in a mountain stream a travel-worn
female salmon is about to create new life.
she cleans and shapes the gravel to form a string of nests called redds
the stream current carries away any fine sediment.
She deposits thousands of eggs over a period of a few days.
Each time, her male partner immediately fertilizes them.
She covers the now-fertile eggs with clean gravel, then stays for a couple of weeks to
defend her nests.
Cold, clean water is crucial for healthy growth and survival.
Water flowing through the gravel continually delivers oxygen to developing eggs
and carries away waste.
Here in the gravel the eggs hatch.
The young, or frye, depend on the yolk sac for nourishment.
These tiny fish with their yolk sacs still attached are called sac frye.
When they're ready
they move upward through the gravel to emerge into the stream.
Once they are one inch long
they are called fingerlings.
They will remember this stream and it's smell,
returning when they are adults to spawn and die just as their parents did.
Time spent in freshwater varies among salmon species from a few days to three years.
The tiny fingerlings grow in backwaters and stream margins.
Here the current is weak and insects provide plenty of food.
As the fingerlings grow
they move to the main channel.
Here the best pools for salmon are deep and contain large wood and rocks for hiding and shade,
for insects and for varrying water speeds.
Carried downstream by the spring thaw salmon begin the amazing changes called smolting
needed to survive in the ocean.
Smolting is triggered mainly by the increasing daylight hours and rising water temperatures
Individual territorial behavior gives way to more cooperative schooling behavior.
Gravel colored markings change to a silvery hue.
Internal changes mostly affecting the kidneys allow for the transition from fresh to salt water.
Estuaries provide a mix of fresh and salt water habitats in which salmon smolts prepare
for entering the ocean.
Swimming out with the tide young salmon leave their home rivers.
Moving around the pacific ocean in varying migratory patterns, they live in the ocean
anywhere from two to five years, growing and maturing.
Ocean life means escaping predators as well as avoiding fishermen
To preserve the dwindling fish runs
fishing limits are set on all taking of salmon.
Researchers have found that while in the ocean
salmon often travel phenomenal
distances in search of food.
During this time they increase in weight. Often more than a hundred fold.
Temperature and food conditions can be highly variable from year to year.
A large percentage of fish do not survive the difficult ocean passage,
especially the early period.
Eventually an instinctive trigger tells mature salmon the time has come to return to their
home stream and reproduce.
Triggered by an irresistible instinct to spawn salmon find their way back to the river mouth,
then head upstream with great determination.
Faced with natural and manmade barriers salmon frequently have to launch their full weight skyward.
While dams block their way, many have fish ladders, like artificial rivers,
allowing fish to swim around the dams.
The homeward bound salmon no longer eat living off of stored fat,
pausing only occasionally to rest.
They endure weeks of struggle against powerful currents up hundreds of miles of river.
Bruised and battered,
wearing to the smarts from unsuccessful predators they swim on to the headwaters, their health
even after spawning, the cycle is not quite complete.
Salmon carcasses have more to give.
Food for the forest, for predators and even for