Chinook salmon are widely prized in the culinary world. Known for its rich and almost buttery texture, it can be roasted, smoked, grilled, glazed—you name it. But more importantly, this Pacific salmon is a keystone species in our environment. This complex animal has the most fascinating life cycle as an anadromous fish, meaning it lives in both fresh and seawater (NOAA Fisheries, 2019). In North America, they live along the coasts of Oregon, Washington, Idaho, Washington, California, Alaska, and Canada. They are also found along the Asian coast, in Japanese and Russian waters.
Its life begins in freshwater. Spawning occurs in freshwater streams and rivers, where the adults lay their eggs. The juveniles then move to estuaries (the tidal mouth of a large river, where the tide meets the stream), and when they have matured enough will migrate to sea water in the open ocean to feed and grow. They can grow up to 3-5 feet and weigh up to 30-110 pounds. Young salmon feed on insects or amphipods, which are small crustaceans; adult salmon feed on other fish like herring, sandlace, pilchard, mackerel, or even squid and krill. Usually after 3-7 years, the salmon will return to their birthstream and breed during the summer or autumn seasons. Female salmon lay from 3,000 up to 14,000 eggs in the redds, or nesting holes that they have dug up (National Wildlife Federation, n.d.). The parents typically die shortly before the eggs hatch, and then the cycle starts over again.
As a keystone species, they play a critical role in diversity and stability of their ecosystems, and the other animals that depend on them like orcas, seals, bears, eagles, to the human population. Without a keystone species, the ecosystem is unable to hold itself together, leading to the devastating collapse of dependent organism populations.
Chinook salmon are “canaries in the coal mine,” an idiom coined to describe early warnings of danger. But what danger could these salmon possibly be in?
Unfortunately, they are at mercy to the dangers of habitat degradation, unsustainable commercial and recreational fishing, dams and culverts or other impediments to migration flow, and climate change. Their populations are at considerable risk, classifying them as an Endangered Species by the Endangered Species Act.
In particular, they are “canaries in the coal mine” for the early warning signs of climate change.
To sustain their complex life cycles from fresh to seawater, salmon need plentiful clean and cold water to thrive. The glaciers and mountains that provide the cold water for their survival are threatened by climate change. The average global temperatures are rising: there was an estimated 1.77 degrees Fahrenheit increase in annual average air temperature from 1960-2020 in Washington, one of the largest homes to salmon (PNW Temperature, Precipitation, and SWE Trend Analysis Tool | Office of the Washington State Climatologist, 2019). As the average temperature rises, mountain snow packs are on decline, leading to a sharp decrease in water from mountain snow. In fact, a study showed that from 1960-2020, the water from melted snow decreased by 21% or 36 km (Mote et al., 2018). A good portion of this water also is consumed by humans for irrigation and municipal purposes. Thus, salmon are left with less freshwater streams, making it more difficult to migrate to oceans and back. By the 2080’s, the summer streamflows are projected to decline from 34-44% in Washington (Snover, A.K. et al., 2013).
As a result of declining water levels, the temperature of the water has risen, exceeding the thermal tolerance of salmon. Water temperatures above 64 degrees Farenheit cause stress to salmon, while any temperature above 70 degrees Fahrenheit can be fatal (Mauger et al., 2015). Warmer waters also increase the risk of predation, and parasite and disease growth.
The amount of precipitation favorable for salmon is also affected by climate change. There is an increase in rain, rather than snow. The winter streamflow in the 2080’s is projected to increase anywhere from 25-34% on average in Washington (Snover, A.K. et al., 2013). Increased winter stream flow poses threats such as flooding. Intense floods can destroy the redds and flush juvenile salmon out of the estuaries before maturity. Flooding severely decreases their chance of survival.
Ocean acidification can also detrimentally impact the salmon. For example, ocean acidification dissolves tiny mollusk shells that the juvenile north pacific salmon feed on. The rise of forest fires in the pacific northwest pose dangers as well, increasing siltation and erosion of the salmon streams (National Wildlife Federation, n.d.).
But what can we do? Conservation efforts include and are not limited to the protection of parks, wilderness, and surrounding environment of the chinook salmon. Dams and culverts in areas like Washington need to be removed to minimize migration hindrances. We can work to save salmon by improving streamside logging protection, forestry management, and farming practices. We can advocate for more sustainable fishing methods. And globally, we can work to conserve energy and use water more efficiently.
Making more sustainable and mindful food choices is also a solution. Restaurants in Seattle decided to remove this salmon off their menus in an attempt to restore the chinook salmon populations. You can also choose to pick alternative seafood options, check your local fish markets, and research whether or not they have been sourced sustainably. Avoiding salmon entirely is not possible for everyone, as many populations depend on it as a major protein source. However, we can all do our best to reduce overconsumption and to discourage overfishing.
In short, climate change is posing and will continue to severely disrupt and destroy the salmon life cycle. Thus, it is essential to protect this fish to prevent the collapsing of other populations in the ecosystems dependent on this keystone organism. Their decline is a warning of the greater and broader scale of destruction we are posing on our planet. There are so many ways each of us individually can work to restore salmon populations. Let us not ignore this warning and act before it is too late.
References
Climate Change Changes and their Affect on Salmon. (n.d.). State of Salmon. https://stateofsalmon.wa.gov/executive-summary/challenges/climate/#:~:text=Water%20temperatures%20greater%20than%2064
DeNies, R. (2021, August 26). Eight Things We Can Do Right Now to Help Salmon Adapt. Wild Salmon Center. https://wildsalmoncenter.org/2021/08/26/eight-things-we-can-do-right-now-to-help-salmon-adapt/
Mauger, G. S., Casola, J. H., Morgan, H. A., Strauch, R. L., Jones, B., Curry, B., Isaksen, T. M. B., Binder, L. W., Krosby, M. B., & Snover, A. K. (2015). Climate Change in Puget Sound. In Climate Impacts Group University of Washington. https://doi.org/10.7915/CIG93777D!
Mote, P. W., Li, S., Lettenmaier, D. P., Xiao, M., & Engel, R. (2018). Dramatic declines in snowpack in the western US. Npj Climate and Atmospheric Science, 1(1). https://doi.org/10.1038/s41612-018-0012-1
National Wildlife Federation. (n.d.). Chinook Salmon. National Wildlife Federation. https://www.nwf.org/Educational-Resources/Wildlife-Guide/Fish/Chinook-Salmon#:~:text=Some%20populations%20of%20Chinook%20salmon
NOAA Fisheries. (2019). Chinook Salmon – Protected | NOAA Fisheries. Noaa.gov. https://www.fisheries.noaa.gov/species/chinook-salmon-protected
PNW Temperature, Precipitation, and SWE Trend Analysis Tool | Office of the Washington State Climatologist. (2019). Washington.edu. https://climate.washington.edu/climate-data/trendanalysisapp/
Snover, A.K., Mauger, G.S., Whitely Binder, L.C., Krosby, M., and Tohver, I. (2013) Climate Change Impacts and Adaptation in Washington State: Technical Summaries for Decision Makers. Climate Impacts Group, prepared for the Washington State Department of Ecology by University of Washington Climate Impacts Group.
Which Animals Are Most Impacted by Climate change? (2023, August 9). IFAW. https://www.ifaw.org/journal/animals-most-impacted-climate-change
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