Salmon, one of the many species of fish that contain lots of nutritional value is very beneficial to humans. This type of fish can live in both fresh and marine waters, and is one commodity fishery products consumed by many people. Apart from all that, the title above will be the main topic of this paper just to add to our collective knowledge.
Salmon life cycle begins in freshwater (rivers), here the eggs hatch salmon eggs (usually in November) and here begins the fight of his life. Salmon mortality rate at this stage is very large. Of the total number of fertilized eggs, approximately half of which hatched. The newly hatched salmon are called "alevin" living in a pile of gravel in the riverbed by eating plankton. Once the food supply runs out, alevin will come out of the gravel riverbed (May / June), at this stage of salmon called "Fry". Fry then grow and develop into a "smolt" which then moved to the mouth of the river to the open sea.
The first year of life in the oceans is a critical stage of salmon predators face. Predators that prey on salmon in large quantities is seals. In addition, sea lions, bears, birds and humans also pose a threat salmon survival.
Long adventure at sea (4-7 years), salmon grow up and mature enough to reproduce. Here lies the uniqueness of salmon, where life begins (hatch of eggs) that's where the salmon reproduction process. Salmon that live in colonies (gathered in abundance) will gather with other colonies salmon migrate back to freshwater to the river.
Salmon return trip is not for a while, take some time to a matter of months. Many obstacles that block his way, through the rocks, swim against the current, leap up waterfalls (salmon jumping power could reach 3 meters), and others.
One more thing, during the return journey, the salmon do not eat anything aka fasting. Reserves of fat in the body is a source of food to get to the fresh waters. Use of this body fat reserves will cause physical changes in salmon. At this stage, many salmon die from injuries, exhaustion or predators, until finally only a few who made it to the river.
From an existing source, no one can be sure how salmon find their way home back to the river where they hatched after swimming in the ocean for many years and thousands and thousands of pounds away. The theory is the most widely embraced salmon aroma which automatically store where she was hatched, and this is what will lead the return trip back to the place of origin.
Arriving at the river upstream (or where hatched), in a state of exhausted salmon will break ground on the bottom of the river to make a hole (25-30cm) to the nest by using its tail. In the hole that the female salmon eggs expend 3000-8000 points and then fertilized by the male sperm of salmon. Completion of fertilization, male and female salmon cover the nest back to gravel.
Both salmon will stay a few days around the nest until death finally runs out of energy. Most salmon carcasses would be eaten by the animals that live in the river, and some will decompose with the aid of bacteria to become a natural fertilizer. The natural fertilizer will be eaten by plankton and small insects in the river bed. In the end, plankton and small insects will be a staple food for the newly hatched salmon a month later.
That struggle and the salmon life cycle. An orphan since hatching, to travel with a very big risk and sacrifice for the survival of the population in the future. Certainly a lot of positives we can take from this story apart from the nutrients contained salmon. May be useful.