Retreating Glaciers May Potentially Create New Salmon Habitats, But Can Just As Easily Hurt Them

A review of:

Pitman, Kara J, et al. “Glacier Retreat and Pacific Salmon.” OUP Academic, Oxford University Press, 11 Mar. 2020, academic.oup.com/bioscience/article/70/3/220/5799047.

A recent article published in the journal BioScience explores the possible impacts of glacier retreat on salmon populations. As climate change raises the temperature of the planet, glacial ice begins to melt - a concern to salmon populations, whose habitats are shaped by glaciers. Glaciers have been rapidly retreating from the range of many salmon populations. Glaciers are predicted to lose up to 80% of their ice volume in western North America. Glacier retreat can alter the habitats currently inhabited by salmon, and also has the potential to create new ones. The scientists cite examples of such activity as evidence, stating that glacial runoff majorly impacts water temperatures, hydrology, and biogeochemical refluxes, among other things. All of these impact the conditions of salmon populations both in freshwater and nearshore marine habitats. This can strain populations of adult salmon and create poor habitats for reproduction and spawning, though cooler temperatures may be beneficial to juvenile salmon, and it is possible that new habitats that are able to support salmon may be formed as a result of flooding and glaciation. The scientists hypothesized that the coming decades will result “in areas in which salmon populations will be challenged by diminished water flows and elevated water temperatures, areas in which salmon productivity will be enhanced as downstream habitat suitability increases, and areas in which new river and lake habitat will be formed that can be colonized by anadromous salmon.”

Essentially, the impacts of glacier retreat can’t be fully predicted. The scientists wrote that “Effective conservation and management of salmon habitat and populations should consider the impacts of glacier retreat and other sources of ecosystem change.” Salmon are not the only fish species that will be impacted by glacier retreat, and it is important to remember that glacier retreat is going to be another factor piling on top of the problems that salmon populations and habitats are already facing, which include habitat destruction, climate change, and fishing practices that decrease salmon biodiversity. It is in our interest to protect these economically and culturally important species.

The scientific article was very thorough - it provided various images, charts, tables, and graphs. In my opinion, it lacked bias and fairly addressed all possible outcomes, instead of leaning towards the negative, as these things tend to do. The only weakness of the article was its extensiveness, and the bit of repetition within the article. The article ended with a positive outlook and a call to action, once again reinforcing the importance of protecting these water-dwelling species.