Lifecycle of a Salmon

The Port Moody Ecological Society raises both coho and chum at our Noons Creek hatchery.  Chum like to head to sea as soon as they are able – these are what are released at our Fingerling Festival on the first Saturday of each May.  A fingerling is a juvenile salmon; it’s about the size of your finger!  Chum like to stay in our pond for a year.

Life cycle of a salmon

Lifecycle of a Salmon

Drawing: salmon lifecycle

Each fall, drawn by natural forces, the salmon return to the rivers which gave them birth. They fight their way upstream against powerful currents, leap waterfalls and battle their way through rapids. They also face dangers from those who like the taste of salmon: bears, eagles, osprey and people.

Once the salmon reach their spawning grounds, they deposit thousands of fertilized eggs in the gravel. Each female digs a nest with a male in attendance beside her.

By using her tail, the female creates a depression in which she releases her eggs. At the same time, the male releases a cloud of milt. When the female starts to prepare her second nest, she covers the first nest with gravel which protects the eggs from predators. This process is repeated several times until the female has spawned all her eggs.

Their long journey over, the adult salmon die. Their carcasses provide nourishment and winter food for bears, otters, raccoons, mink and provide nutrients to the river for the new generation of salmon, much as dying leaves fertilize the earth. The two other salmonids, cutthroat and steelhead trout, may survive to go back to sea and possibly return to spawn again.

As the salmon eggs lie in the gravel they develop an eye – the first sign of life within. Over months, the embryo develops and hatches as an alevin. The alevin carries a yolk sac which will provide food for two to three months. Once the nutrients in the sac are absorbed, the free-swimming fry must move up into the water and face a dangerous world.

The fry may live in fresh water for a year or more, or may go downstream to the sea at once – it varies by species. Fry ready to enter salt water are called smolts. Whenever they do migrate, they face predators, swift currents, waterfalls, pollution and competition for food.

Young salmonids stay close to the coastline when they first reach the sea. After their first winter, they move out into the open ocean, and, depending on the species, spend from one to four years eating and growing in the north Pacific Ocean. Then they return to their home streams, spawn and die.

From each thousand eggs that were laid, only a few adult salmon survive to perpetuate their species. Hatcheries, like Robertson Creek, greatly increase the number of survivors by protecting the eggs and fry through the critical early development of their life.

(Text provided by the DFO Oceans, Habitat & Enhancement Branch)

http://www.pac.dfo-mpo.gc.ca/fm-gp/species-especes/salmon-saumon/facts-infos/cycle-eng.html