Pacific salmon are a resource of critical importance to both human and wildlife communities, throughout marine, freshwater, and terrestrial ecosystems. Pacific salmon are anadromous fishes. Anadromous comes from the Greek word anadromos, meaning “running upward.” Anadromous fish are born in freshwater ecosystems– rivers and streams– and travel out to sea within the first couple years of their lives. They then spend most of their lives at sea, growing more massive each year, before migrating back to their natal freshwater streams (the areas in which they were born), running upriver to breed and die.
This cycle provides valuable nutrients to a host of species. Vital elements in salmon carcasses, such as nitrogen and phosphorous, leech into soils, helping terrestrial plants to grow. Live salmon, salmon roe, and senescent carcasses provide food to a host of fish predators and scavengers, including brown and black bears, wolves, coyotes, bald eagles, marten, mink, ravens, magpies, and voles. Salmon carcasses are breeding sites for invertebrate species, such as flies, carrion beetles, and mites.
Salmon are important to human communities, too. Subsistence fisherman depend on yearly salmon stocks. Commercial salmon fisheries in the Pacific generate millions of dollars of economic profit annually. And salmon generate additional economic revenue through tourism– along with sportfishing, tourists flock to salmon spawning areas for wildlife viewing and unparalleled opportunities for photography.
Historically, millions of salmon spawned up freshwater streams from the ocean, provisioning human and wildlife communities. However, land use changes, such as increasing urbanization and agricultural conversion, as well as overfishing, climate change, and water contamination, have adversely impacted salmon populations, and salmon have disappeared from greater than 40% of their historic range.
Our research looks to identify the links between Pacific salmon and terrestrial wildlife. What species rely on salmon for subsistence, and to what extent? How are the life cycles and behavior of different terrestrial wildlife species influenced by salmon availability? What are the direct and indirect impacts of salmon on terrestrial environments, and how far do these impacts spread across time and space?
There are five different species of salmon that spawn in the eastern Pacific up freshwater rivers and streams along the west coast of the United States: Chum, which also known as Dog or Keta; Coho, also known as Silvers; King salmon, also known as Chinook; Pink, or humpback salmon; and Sockeye, or red salmon.
If you’d like to learn more about our experiences with salmon and our research, check out the following blog posts on Pacific salmon spawning in southeastern Alaska: