Adult male and female salmon
spawn simultaneously with their mouths gaping.
Their fertilized eggs are deposited in a redd
(gravel nest) located in a streambed
or along a lakeshore. The female salmon is responsible for digging the redd using undulating
(sweeping) movements of her tail, while the male protects the female from intruders
(other potential spawners). The embryos (fertilized eggs) hatch and develop into alevins (yolk-sac fry) which live off their nutrient rich yolk-sac
that is attached to their underside. The young alevins will emerge as fry from the redd
when they absorb their nutrient rich yolk-sac and start actively searching for food. Alevins
that emerge from the redd before they completely absorb their yolk-sac are commonly called
button-up fry. The small vulnerable fry will start to develop
parr
marks(vertical bars) on their sides as they start to feed and grow. The parr
marks generally last a few months to years depending on the species of salmonid.
Resident species of cutthroat trout retain their parr marks throughout life.
After a period of growth in fresh water, anadromous species will start their downstream
migration to the sea. The silvery smolts will undergo a series of physiological
and morphological changes that allow them to acclimate (adjust) to the salt water
conditions of the new marine environment. Once in the ocean, the smolts will feed and grow to
fully developed adult salmon. Some salmon called jacks/jennies (precocious) will return
to their natal stream to spawn (reproduce) earlier than the rest of their age-class.
Salmon that have spawned are called kelts. Most salmon spawn only once during their
lifetime (semelparous), although some salmonids, mainly steelhead, are iteroparous
(have the ability to spawn more than once). The majority of the salmon species die within
a week of spawning. The nutrients from their
decomposing bodies help to fertilize the stream.
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