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We have three 6th grade Science classes and two 8th grade Science classes blogging here from the Pacific Northwest in Chimacum, WA! Sixth graders are learning a bit about Mt Saint Helens, environmental science through fresh water ecology, and physical science this year. Eighth graders are learning about life science this year. Please join us as we learn Science by exploring our world.
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Salmon Life Cycle There is a very confusing question out there. "Which came first, the chicken or the egg?" Well wouldn't that work with any animal that lays eggs? Of course it would! So I am going to go through the entire salmon life cycle to find out which came first, the salmon or the egg?

The Egg Stage

Salmon eggs are usually a reddish orange color. They have a black dot right in the middle. This is the salmon egg's eye. The mother protects the eggs by digging a hole, like a burrow, called a redd. The eggs are then shielded by a layer of gravel. Eggs are threatened by predators, pollution, high temperature, and gravel disturbance. They need cold water and lots of shade.


Alevin stage

Alevin is the second stage of the salmon life cycle. They are small and have a little sac hanging from their belly. This is a yolk sac. The little fish are fed this through their yolk sac. They are theatened by gulls and other big fish like trout. Alevin need gravel to hide from predators.
src="http://educatoral.com/rm604/images/per5/g1/marcusalevin.jpg" width="400">

Fry Stage

Once salmon hit the fry stage, they start to look like normal fish. They need lots of woody debris to hide under. They also need a cold environment with sediment free gravel. Loss of riparian habitat is a huge threat to salmon. Riparian habitat is The community of plants around water that is concentrated.This is really important to salmon.
src="http://educatoral.com/rm604/images/per5/g1/marcusfry.jpg" width="400">

Parr Stage

The parr stage of the salmon life cycle is an interesting one. They grow black stripes on their backs for camouflage. Parts are threatened by loggers and especially blue heron. They need their parr marks to protect themselves from predators like birds. Parr need lots of food.
src="http://educatoral.com/rm604/images/per5/g1/marcusparr.jpg" width="400">

Smolt Stage

Smolts look almost exactly like parrs exept they don't have parr marks. Smolts are often sucked up in hydroelectric dams. That's why people put up nets to scare the smolts away from the dams. The smolt stage is usually when they start to swim to the ocean, but they can't be exposed to salt. So they start to grow a grey skin color that is salt tolerant.
src="http://educatoral.com/rm604/images/per5/g1/marcussmolt.jpg" width="400">

Adult Stage

The adult stage is the second to last stage of the salmon life cycle. Adults are threatened by orcas and seals, and there is a huge fish out there called white sturgeon and they grow huge by eating tons of salmon. So those are threats too.
src="http://educatoral.com/rm604/images/per5/g1/marcusadult.jpg" width="400">

Spawner Stage

The spawner stage is the last stage of the salmon life cycle. Once they reach the spawner stage their mouths curve upward and they grow sharp teeth to defend their spawning grounds. Once they spawn, they die.
src="http://educatoral.com/rm604/images/per5/g1/marcusspawner.jpg" width="400">

So, I guess, even by going through the entire salmon life cycle, we don't know which came first the salmon or the egg.



Article posted January 4, 2012 at 03:22 PM • comment • Reads 1045 • Return to Blog List

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