Friday, April 27, 2012

How Salmon Are Made

It's spring time and the salmon are running.  This is not news to most of you who crave the delicious flavor of wild salmon.  By now you realize that you can only get really beautiful, fresh wild salmon during the spring and summer months, but exactly why, and more importantly how this happens may be a little clouded.  Let's shed some light on this process of survival and reproduction.

Ivory King Salmon
The major wild salmon runs for us take place during the spring, summer, and fall months on the west coast of the U.S.  Commercial fisheries exist in the states of California, Oregon, Washington, Alaska, and there are also some in Canada.  Wild salmon are anadromous, meaning that they are born in fresh water and then migrate to salt water.  Typically salmon will spend anywhere from 1 to 4 years in salt water until it is time for them to return to the exact stream in which they were born.  This is an amazing feat seeing that they have not revisited this spot since birth and have swam thousands of miles since.  Imagine finding your way back to the hospital in which you were born without a map, smart phone, or GPS after spending several years miles away with only your memory to guide you.  Sound tough?  Well millions of salmon do this every year and they accomplish this feat with their sense of smell.  When salmon are born their natal environment is 'imprinted' on them through their olfactory senses, and this imprint stays with them throughout their entire life.

This scent is activated when water temperatures or other environmental changes trigger salmon to return home to spawn.  Different species or even different 'tribes' (salmon of the same species but birthed in different areas) of salmon return during different times of the year, that is why we have different runs.  There are salmon who return to rivers in waters closer to the ocean and others that go farther up the river.  These differences can exist in salmon of the same species swimming in the same rivers.  Most salmon that are caught for food are caught while they are still in the ocean or early in their journey.  The reason being that a salmon transforms when it begins its long haul to reproduce.  A salmon stops feeding once it enters fresh water.  Their stomachs disintegrate and the empty space is utilized for eggs and sperm.  During this time salmon are feeding off of their fat stores located in their muscle tissue.  The proteins begin to break down and their flesh becomes flabby and tasteless.  You sometimes see this if you have purchased an 'old' salmon.  It does not mean that the fish has been out of the water for an extended amount of time, just that it was caught too far up the river and its meat has begun to breakdown.   A salmon's outward appearance also changes.  Most salmon will display a kype, or a hooked nose.  This kype helps them display dominance over other salmon and fight for females.  Other salmon like pinks and sockeyes develop humped backs.  Sockeyes also turn a really beautiful bright red, and most other salmon species turn colors in some way.

Once in the fresh water, males usually arrive first and battle for the best breeding grounds.  Gravel beds with a slight water flow are the most preferred.  When the females arrive spawning begins, the males can't do it by themselves.  The females initiate the action, naturally, by using their tails to dig redds or nests in the gravel.  So while the males are fighting the females are domesticating their area, hence the term used amongst our own species, 'nesting'.  After the redd is completed the female will release her eggs and the winning male will come to her side to release his sperm or milt, to the victor goes the spoils.  Just about one in every thousand eggs will make it out of the river and into adulthood, so the odds are not great.  The male and female salmon will repeat this process until all of the eggs and milt are relinquished, a female salmon can produce anywhere from two to ten thousand eggs.  Then, after their fight up the river is over and they have paved the way for the next generation, salmon, with all the dignity in the world, die.  Their corpses scatter the riverbanks and become food for many different kinds of animals.  These gallant salmon have only one purpose in life, to get back home and produce baby salmon.

It's amazing to think that a salmon is on its own from birth.  That they are thrown into the world with only their DNA to guide them.  It is a feat of nature that they make it out of freshwater, let alone come back to the very place in which they were hatched in order to make way for the next generation.  Their missions are always upstream; salmon always go against the current.  I admire them for several reasons, their determination and self-reliance is awe inspiring.  I have heard some people lament the fact that salmon work so hard and strain their bodies to such limits, just to die afterward.  I do not agree with this sympathy.  I believe that after spawning every salmon dies 'happy', if there is such a thing.  They live with a clear purpose and die after seeing that purpose fulfilled.  One in a thousand aren't the best odds, but after miles of fighting current and starvation, they're the best a salmon can get.

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