Discover why these wild fish work so hard to swim back up rivers
The other night, while I was enjoying some sushi, a question suddenly popped into my head: why on earth do salmon swim upstream? Just think about how exhausting that must be!
They spend their lives swimming peacefully in the ocean, feeding on plankton and minding their own business, and then, all of a sudden, something clicks and they decide to take on an upstream marathon, making their way up rushing rivers as if there were no tomorrow.
But why? And above all, what makes them do it?
To answer that, let’s take a closer look at the life of salmon and understand why, instead of staying in salty water and taking it easy, they choose to go through an epic journey back toward the headwaters of rivers. Get ready, because the story is even more incredible than you might think!
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Anadromous: the technical word that explains this madness
So why do salmon make such a fuss? The answer lies in a complicated word: anadromous migration.
Basically, “anadromous” means that salmon are born and grow up in freshwater, then head out to live the good life in the salty waters of the ocean, and finally, when it is time to reproduce, return to the river where they were born.
A bit like people who leave their small hometown to enjoy life in the city, where nobody knows them and nobody can gossip about them... and then, when they grow older, they return home to enjoy a quieter life.
Except salmon, instead of coming back to relax at the local café, return in order to become parents.
And that is the interesting part! Because to get back home, they have to face an extraordinary effort.
But why go through all that trouble? Why not do it comfortably in the sea like most other fish?
Fresh water: the salmon’s reproductive secret
The reason is simple, but not that simple: salmon need freshwater for their young to hatch. Yes, because salmon eggs are extremely delicate and need fresh, cool, well-oxygenated water in order to develop and hatch into baby salmon.
Saltwater from the sea would be too harsh for these delicate embryos.
And there you have it: mystery solved!
So, in order to bring their young into the world, salmon have no choice but to return to the rivers where they were born. And it does not matter if that means travelling mile after mile against the current, leaping over waterfalls and battling rapids and even bears waiting with open jaws.
The instinct to reproduce is stronger than anything else, even the exhaustion and dangers awaiting them.
A dramatic journey of survival worthy of a Hollywood thriller
And what a journey it is!
Some salmon undertake true odysseys, swimming upstream for nearly 5,000 kilometres! Practically speaking, that is like swimming from Rome to Moscow.
And not only do they have to swim against the current, they must do it without eating. During this extraordinary journey, salmon do not feed; they survive only on the fat reserves built up during their life in the ocean.
All this effort serves one single purpose: reaching the right place to reproduce and lay eggs. Females can lay up to 2,000 eggs for every kilo of body weight.
And the males are there too, ready to fertilize this huge number of eggs.
After spawning comes the end of the journey
But the story does not end there. After spawning, salmon are completely exhausted, drained of all energy. They have used every last bit of strength for this incredible journey and for reproduction.
And then, many of them die.
Yes, after becoming parents, many salmon reach the end of their life cycle. It is a harsh ending, to say the least.
Worn out and with no strength left, they are carried by the current back toward the sea, this time in the opposite direction. Unfortunately, in such weakened conditions, they become easy prey for predators. Bears, eagles, seals, gulls—many animals compete for a share of the fish.
And many exhausted salmon end up stranded along riverbanks, left there by the current. A dramatic scene indeed...
A tough life, but vital for the ecosystem
That is the life of a salmon: born in a river, raised in the ocean, making an immense effort to return home, reproducing, and then dying.
What is all this for? To ensure the survival of the species, of course, but also to feed many other animals.
Dead salmon become a true feast for river and coastal ecosystems. Their decomposing bodies release valuable nutrients that fertilize the waters and nourish plants and other animals.
So next time you wonder why salmon swim upstream, remember that they do it for their offspring, out of survival instinct and, in the end, also to support the environment.
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Pay tribute to these salmon heroes: come see them in Alaska!
If this whole salmon story has sparked your curiosity and you would like to visit the places where their odyssey unfolds, Alaska is the destination for you.
There you can find five different species of wild salmon, all born in the same crystal-clear rivers and all ready to make a tremendous effort to return home.
We will take you to see these remarkable fish with your own eyes as they fight their way upstream. We will go trekking in some of the most spectacular places in Alaska, from Denali National Park to the Gulf’s fjords, where you may spot plenty of whales. Then we will head to Russian River Falls, a place where bears feast on salmon in unforgettable scenes of wild nature.
Do not miss the chance—book your place now with Sto Gran Tour for the edge of the world... which truly feels like the edge of the world! Enjoy our 13-day trip to Alaska!
