When a salmon swims up a river to breed, it often has to jump up waterfalls. The figure shows a salmon jumping above the surface of the water. On this occasion the salmon falls back down into the river.
When do salmon spawn in a river system?
Many people know that salmon spend most of their adult lives in the ocean and that they swim upriver to spawn in freshwater. But when exactly do salmon spawn once they have entered a river system? Most salmon start to swim upriver during late spring and summer but won’t spawn before fall or early winter.
Why do salmon swim upstream?
The short answer to this is “to spawn”. Salmon are born in freshwater, usually in cool fast-flowing water. They live in the river for about two years before making their way out to sea.
One of the next things we wanted the answer to was, why do salmon have to swim upstream?
The answer is all salmon are born in rivers streams and all of them return to the same river or stream they were born in to give birth to a new generation of salmon. As they can locate their specific natal spawning grounds, they have to swim upstream to get there.
Do salmon jump in rivers?
Salmon often jump in rivers to get over obstacles that would otherwise prevent them from continuing their journey upstream. Common obstacles and barriers include dams, waterfalls, and culverts. Other obstacles that salmon may have to jump over include sunken trees, floating logs, and simply rapids.
Every year when it’s time to mate and give birth, the salmon return from their feeding grounds to the places where they were born. For some, this can mean a trek all the way across the Pacific Ocean. For others, it’s a simple swim back up the river. For all, it means a tough journey upstream almost the entire way.
The run up the river can be exhausting, sometimes requiring the salmon to battle hundreds of miles upstream against strong currents and rapids. They cease feeding during the run. Chinook and sockeye salmon from central Idaho must travel 900 miles (1,400 km) and climb nearly 7,000 feet (2,100 m) before they are ready to spawn.
How do salmon survive in streams?
Salmon enter fast-flowing freshwater systems and swim up their natal rivers to find a suitable spawning location. The rivers’ running water and habitat provide both plenty of oxygen and shelter for the eggs and juvenile salmon, which increases their rate of survival.
How do salmon find their spawning grounds?
According to studies, salmon use both the earth’s magnetic field and their highly developed sense of smell to first find their natal river and then their respective spawning ground. This amazing ability is evolution at its finest! The salmon never seem to swim up the wrong river and always know exactly how far upstream they have to go.