Salmon are coming home after a century
Various media – like the Associated Press on November 16, 2024 – are reporting this month that hundreds of salmon are returning to their ancestral spawning grounds on the Klamath River in southern Oregon and northern California. Their return closely follows what experts have called the world’s largest dam removal effort.
Completion of the demolition of four hydroelectric dams on the Klamath River came a month ahead of schedule, AP said, and right in time for salmon mating season!
The National Oceanic and Atmospheric Administration (NOAA) had commented last summer on the dam removal project. NOAA said it restores 420 miles (676 km) of watershed habitat for salmon. NOAA Research Fisheries biologist Tommy Williams also called it a “boon” for the salmon ecosystem, saying:
When you simplify the habitat as we did with the dams, salmon can’t express the full range of their life-history diversity. The Klamath watershed is very prone to disturbance. The environment throughout the historical range of Pacific salmon and steelhead is very dynamic. We have fires, floods, earthquakes, you name it.
These fish not only deal with it well, it’s required for their survival by allowing the expression of the full range of their diversity. It challenges them.
Why were the dams built?
Built from 1908 to 1962, the purpose of these dams was to provide electricity to cities, farms and mines in the region. The dams’ purpose was not to store water for drinking or irrigation or to prevent flooding.
Indigenous tribes were among those who suffered the effects of the dams. The Yurok tribe, which has always inhabited and managed the forests, rivers and coastal areas throughout Northern California, watched as salmon, sturgeon, trout and others lost their breeding grounds following the construction of the dams.
Why were the dams removed?
The U.S. federal government currently owns and self-regulates only 4% of dams; most are privately owned. PacifiCorp was the current private owner of the Klamath River dams in question. And these dams produced less than 2% of the energy the company supplied to their customers.
In the face of numerous protests and hundreds of millions spent on federally ordered improvements for maintenance and sustainability, it was agreed that four of the eight dams should be demolished.
Will the past decades of damming forever change the future of this river? It’s too soon to say. However, local tribes have been reporting they are already seeing hundreds of salmon arrive in the newly released tributaries.
What are the benefits of the dams’ demolition?
When the dams were operational, the water behind them was said to be a hot soup filled with bacteria and algae. In fact, in 2002, the Klamath River suffered severely from an unprecedented lethal event: a branchiomycosis (gill rot) epidemic that killed approximately 34,000 fish. This was caused by rising water temperatures and low river flows.
Now four dams have been demolished, and it’s estimated that – by early next year – every remaining piece of concrete once a part of these four dams will be removed. The project reopens hundreds of miles of habitat for threatened fish that had been isolated from their original breeding grounds for more than a century.
Salmon are migratory fish
Having open, clean and fresh waterways is important because adult salmon return from the sea to the rivers where they were born to spawn or lay their eggs. In fact, they are anadromous fish, which means that they live both in fresh water, which is where they hatch, and in salt water, which is where they live most of their lives.
They also have a strong, flexible tail fin that helps them swim against the current to return to the rivers where they were born. They can even swim at 31 miles per hour (50 kph). Impressive!
Salmon reproduction is amazing
Did you know salmon change color? Young salmon are silvery but, as adults, they develop a darker color with spots. And that’s not the only thing that changes. When breeding season comes, males modify their jaws. The lower jaw curves upward, giving rise to a hook.
This change in the salmon’s mouth allows it to have the best weapon to fight with other males for females. In fact, the size of this weapon is enough to deter less-developed competitors.
Males defend the areas of the river that are best suited for laying eggs and attack other males that come close. Females, which have hardly undergone any physical changes, dig into the gravel to deposit their eggs, which they cover up later. Then, they leave the area while their partner stays for several days or even weeks.
But the most surprising thing is that after breeding, males develop teeth again and lose their hook. Those who manage to survive and return to the river the following year transform once again. But then their jaws will be even larger.
Are all salmon orange?
Some salmon are orange inside, which is a rare color in nature. These fish are carnivorous, feeding on smaller fish, crustaceans such as shrimp, and insects. Thus, the color of their flesh depends on the number of crustaceans they consume. The more crustaceans they eat, the more pink or red their flesh will be. This is also true of flamingos. What curious animals surround us!
Bottom line: Salmon are coming back to their ancestral homes after the demolition of four dams on the Klamath River, which flows along the California-Oregon border.
Like what you read?
Subscribe and receive daily news delivered to your inbox.
More from
Cristina Ortiz
Carnivorous wolves feed on nectar: Lifeform of the week
Camels are adapted to desert life: Lifeform of the week
Sunflowers are pretty and helpful: Lifeform of the week
Pufferfish are cool but deadly: Lifeform of the week
