Wildlife
Historically, the Columbia River has been home to millions of salmon, mainly Coho and Chinook salmon, and steelhead trout each year. But, throughout the 20th century, “millions” has decreased to “about a million” per year. Local fishermen and Native American tribes along the Columbia have depended on this abundance of fish. The decrease in these two major species is due to the building of many dams, poor water quality in areas of the river closer to industrialized land, and some habitat destruction. Additionally, lesser known fish species in the Columbia River have become endangered as a result of these same issues (Columbia Riverkeeper). The graph to the right represents the general life cycle of salmon: Chinook salmon return to the Columbia River in the fall, spring and summer, and Coho salmon return in the fall. The first graph below represents salmon abundance by year. The amounts of salmon spawning in the Columbia prior to the 1940s was far greater than after. "With the building of main-stem dams on the Columbia beginning in the early 20th century and ending in the 1970s, hatcheries were the tool used to replace salmon abundance reduced by the dams. By 2013, an estimated 80 percent of the returning Columbia Basin adult salmon were born in hatcheries" (Salmon Abundance).
Many animal species, including deer and elk, thrive on the plants and shrubs that grow in lush, riparian zones along the river. Vegetation is not only important for animals, but also for the health of the River itself and the fish it contains. Vegetation acts as a filter, keeping soil, silt and other pollutants out of the water. When flooding occurs, these pollutants can easily end up in the river, impairing the fish (FWEE). However, recent rainfall in the Northwest has led to more salmon returning to the river. But, that still means that close attention must be paid to local ecosystems to ensure that the river water stays as healthy as possible. |
All Images found on the "Wildlife" page can be found at http://oregonstate.edu/instruct/anth/smith/SalmonAbundanceandDiversity_s14002.pdf.