The life cycle of the wild salmon begins with the female salmon digging out a shallow redd, or nest, in the gravel on the river bottom. After eggs are fertilized by the male, the female covers the eggs with small to pebble sized gravel. Gravel covering allows water to flow around the eggs and keep them healthy.
Redds are fragile and can easily be destroyed by people or animals crossing the shallow river or by dirt being washed or knocked into the water and smothering the eggs.
Salmon eggs need cool, clean Water to survive. Trees and plants along the side of the river provide shade which keeps the water temperature cool enough for the salmon eggs. Trees and plants also prevent soil erosion which will sometimes smother the eggs.
The eggs are laid in the fall and hatch the next spring. The small larval fish, about one inch in length are called Alevin and still have a yolk sac attached. The yolk sac contains protein, sugar, minerals, and vitamins. The Alevin live on this "lunch bag" for a month or so before emerging from the gravel and beginning to hunt for food themselves. When the Alevin completely absorbs their yolk sacs, if they leave the gravel before their yolk sac is completely absorbed they are commonly called button-up fry.
Alevin need cold running water that is rich in oxygen and clean gravel that has spaces where the Alevin can hide. Threats include predators in the water, siltation, pollution and floods or other activities that can disturb the gravel can be very harmful, so people can protect the Alevin by keeping dirt or other pollutants out of the water and by staying out of the gravel!
The young salmon fry begin to move in schools and feed in the river. They feed mainly on zooplankton until they grow large enough to eat aquatic insects and other larger foods. Some species of salmon fry, such as chum and pink, start downstream toward the ocean immediately after emerging from the redd; others stay in fresh water for up to three years. Land-locked salmon, such as Kokanee, never migrate to the sea but live their entire lives in fresh water. Loss Riparian habitat along streams, rivers, estuaries, and bays is one of the most serious dangers to the wild salmons survival.
As the salmon parr begin migrating toward the sea, they will, they will begin the smoltification process. The smoltification process refers to The changes that take place in salmon as they prepare to enter the sea. These changes include the development of the silver color of adults and the tolerance for salt water.
LIFE IN THE SEA
The salmon will feed and grow in the sea for the next one to eight year. They will remain in the sea until they reach full maturity. The salmon will also remain silver color until they return to their home stream.
Once the salmon start upstream toward the spawning grounds, Tray do not feed but derive energy from stored fats. The distance salmon travel upstream to spawn varies. The average spawning trip distance is about 150 miles.
About the Blogger
height="267" width="200" classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000"codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=9,0,28,0" id="widget_name">