Salmon

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Bradán

Salmon are native to two of the world's greatest oceans and the rivers draining into them. The Atlantic Ocean only has one species of salmon, but you can find several species of salmon in the Pacific Ocean e.g. pink salmon, coho, sockeye, chinook and amago.


In Ireland, Salmon are often bred on salmon farms.

The Irish salmon come from the Atlantic Ocean. When they are young, they stay in the freshwater rivers before venturing out into the big ocean to grow into adults.

Lets take a look at the life-cycle of the salmon!

Life-cycle of the Salmon

Salmon are an anadromous fish. This means that it breeds in freshwater but lives for most of its life at sea where it can grow and feed before returning to freshwater to breed.

The female salmon digs a small hole in the bed of the river and puts the eggs inside this newly formed redd, or nest.

Once the eggs have been fertilsed, she covers them up with gravel to protect them.

The parents have now given them all the care they can, and leave the eggs to hatch and develop on their own!



 

Before a salmon grows up into an adult, it goes through five different stages of developement.

  1. Eggs: the eggs will hatch after about 180 days, usually in March or April.
     
  2. Alevins: the newly hatched eggs are called alevins. They feed from a small yolk sac attached to their body. When all the sac is finished, they start to swim up out of the nest towards. Soon, all eight of their fins will grow and this helps them to balance in the flowing water.
     
  3. Fry: this phase is also known as the 'swim-up' phase as the young fish must learn to swim to the surface for gulps of air. The air helps them to stay bouyant in the water and makes it easier for them to swim.
     
  4. Parr: very quickly, fry develop into parr. Their skin develops vertical stripes and spots so they can stay hidden from dangerous predators and they can live for up to three years in the river.
     
  5. Smolt: once the parr have reached ten to twenty-four cm in length, they undergo a big change.
    They now develop the ability to live in the salty seawater and not just in the freshwater river. They loose their stripy boday and become a shimmering silver colour. Now  they are able travel together up to the North Atlantic to feed and grow into adults!
     
  6. Adult salmon: sometimes it can take over two years for a smolt to reach adulthood. Then, the  adult salmon will return to its birth-river to spawn. Once a salmon has spawned, it is called a kelt, and the cycle begins all over again!

Salmon Smolt
Copyright The Irish Marine Institute