What creatures navigate oceans, climb mountains, feed forests, and motivate us to destroy renewable energy infrastructure?
The Pacific Salmon! (Oncorhynchus)
This week, we revisit Fred Jennings’ 2021 piece on Pacific Salmon and share some good news: on the Klamath River, the largest dam removal project in U.S. history is already delivering the kind of recovery Fred’s original article envisioned, with salmon reoccupying habitat blocked for over a century.
How do salmon find their way home?
Pacific salmon are famous for their migrations from the saltwater habitats they live in as mature adults to the freshwater rivers and streams where they were born and return to spawn. Salmon have two means of finding their way back to where they first hatched, often to the very same patch of gravel.
In the open ocean, they have a GPS system based on the earth’s magnetic fields sensed through their lateral line (a highly-sensitive line of nerves running down each side of their bodies). When they get near shore, they then follow smells that they imprinted from their natal river up to where they originally hatched, to spawn again and continue this cycle.
How do salmon manage to get back upstream?
Salmon make their way back home against the current of streams and rivers, even climbing mountains in the process. As they go, they feed upland forests by transporting ocean nutrients into the headwaters of their natal streams, supporting all kinds of life in the process (and not just hungry bears)!
What happens to Pacific salmon after they successfully spawn?
Spawned-out Pacific salmon all die after completing their journey. In late fall, on a salmon river, rotting corpses and dying fish appear everywhere, white with mold and stinking with decay. In doing so, they feed forests and the aquatic life that sustains the next generation of fish when they hatch in the spring. We don’t really know why they all die after spawning, unlike the Atlantic salmon, which live after the process is complete.
Bears also increase the ecological reach of these salmon by catching them in rivers and streams and carrying them deep into the forest to feast. This brings their helpful nutrients, particularly nitrogen, into dense stretches of forest where they can fertilize the ecosystem and help trees grow. In fact, it is estimated that eighty percent of the nitrogen in the trees of the Great Bear Forest in Canada comes from salmon. Learn about the interdependent links of salmon, bears, and forest health here.
Where do we find Pacific salmon?
Pacific salmon are an anadromous species, which means they live in seawater but spawn in freshwater. They hatch from eggs in gravel and spend their early years in freshwater rivers up high in the mountains and forests along the Pacific coast. Then, once they reach about 6-8 inches in length, they move down through the estuarial waters to spend several years in the open ocean, feeding and growing large, before they journey upstream to spawn and die.
What is the cultural significance of these fish?
Pacific salmon are part of a religious cycle of life for Indigenous peoples on the American and Canadian West coasts as well as across the planet. Their annual return is celebrated as part of a natural process in which Autumn brings a bountiful harvest of fish to add to other stores of food to last through a long cold winter. Salmon are objects of worship by coastal native inhabitants, human and nonhuman alike, who depend on the annual return of these salmon in the fall to help them get through a long cold winter.
into the East Fork Owyhee River by the Shosone-Paiute Tribe (May 28, 2015)
(Photo by Jeff Allen, Northwest Power and Conservation Council)
We want renewable energy sources! So why are we destroying them for these salmon?
From the 18th into the 20th centuries, our human thirst for factory power had us constructing many dams on our rivers, with little attention to their harmful ecological impact. Many of our anadromous fish species – adapted to the specific conditions of their river watersheds – were lost forever when dams left them unable to complete their journeys upstream.
It is only in recent decades that a powerful movement for dam removal and habitat restoration has been gaining momentum as a means of saving these precious species. The beneficial effects of removing these barriers have been spectacular, as rivers – freed from their shackles – blossom with new life. Along with the salmon have come a revival of other runs, including steelhead, herring, eels, shad and other diadromous fish (ones that transition between freshwater and saltwater environments), as well as birds and wildlife previously not seen in these areas. Our rivers are showing us all that we lost and all the flourishing that is possible once we get out of their way.
The Klamath River Comes Back to Life
Nowhere is this more visible than the Klamath River. In the largest dam removal project in U.S. history, four hydroelectric dams came down between 2023 and October 2024, reopening roughly 400 miles of historic salmon habitat that had been blocked for over a century. The results have exceeded even optimistic projections: within ten days of the final dam removal, more than 6,000 Chinook salmon were already migrating into newly accessible water. Of the fish that returned, roughly 13,000 pushed past the former dam sites into the upper basin, a share far higher than the usual rate at which salmon stray beyond their birth grounds. Tribal nations have been central to this recovery: because salmon had been absent from the Klamath Tribes’ ancestral territory for so long, federal agencies initially didn’t recognize them as eligible for a joint restoration grant, until the neighboring Yurok Tribe stepped in and applied on their behalf, passing the funding through so upper basin restoration work could move forward. Read The Klamath Tribes couldn’t get federal dollars for salmon. Then the Yurok stepped in for the full story.
How are human activities impacting these salmon?
Pacific salmon are in serious trouble. A thirst for hydropower has placed them at dire risk of extinction. We are removing dams, building fish ladders on existing dams (since their proper design is crucial), making sure culverts and other means of fish passage stay open and unhindered. But salmon are cold water species, so a warming planet puts them in peril.
However, there is much we can do to protect them, and restore them once they are threatened or lost.
- See several short but informative videos on salmon restoration efforts.
- See updates on the ongoing Klamath River recovery.
May we keep supporting the Pacific Salmon,
Fred
Fred Jennings is from Ipswich, MA, where he has spent most of his life. He is an ecological economist with a B.A. from Harvard and a Ph.D. from Stanford, both in economics. Fred is also an avid conservationist and fly fisherman. He enjoys the outdoors, and has written about natural processes and about economic theory. He has 40 years of teaching and research experience, first in academics and then in economic litigation. He also enjoys his seasonal practice as a saltwater fly fishing guide in Ipswich, MA. Fred joined Biodiversity for a Livable Climate in 2016.
Thank you. I felt a surge of awe at the salmon story.