King Salmon Dethroned by Invasive Species in the Great Lakes

by megpunter on November 10, 2017 - 11:55pm

King Salmon Dethroned by Invasive Species in the Great Lakes



An optimistic view is taken on the rapid decline of the King salmon population in the Great Lakes by the Michigan fisheries division. King salmon is a largely economic species of the Great Lakes, only introduced to the bodies of water 50 years ago, originating from the Pacific Northwest. The state of Michigan had recently stocked the Great lakes with approximately 1.7 million salmon, just 5 years ago, but was cut to 330,000 this year.  This rapid decline in this particular population can be attributed to the ever-growing presence of the invasive zebra and quagga mussels in the Great Lakes, the greatest colonization since the English. These invasive species has indirectly affected the salmon by decreasing the abundance of alewife, the King salmon’s primary food source. To combat this, the state has taken steps towards re-establishing the alewife by cutting the number of salmon stocked into the lakes so that predation will decrease and they are given a chance for regrowth. It has seemed to be working, as local fishing business to Lake Michigan have noticed an increase in the alewifes population, and are not too worried about the future as management practices have seemed to be working, though it is still early.


This lack of worry about the future despite uncertainty, I think is a product of well done management practices. I do believe it is still early for fishermen to be too optimistic about the fate of the King salmon. One year of increase in the number of alewife does not come with a guarantee that the upcoming years will follow. Though, this positivity exhibits that all actors are pleased with the steps being taken to mitigate the effect of the problem that has arisen, the invasive mussels. I can see that there is an absence of conflict, though uncertainty remains, but it still being handled well. The Michigan Department of Natural Resources has taken its best action using adaptive management to solve the issue at hand. The fisheries have accepted that the ecosystem of the Great Lakes is changing, and they can do their best to maintain the species but they cannot control it perfectly, and will have to rely on different species in the future if need be. Their goal is surrounded around the idea of adding resilience to the ecosystem rather than creating a quick fix, a key feature of adaptive management (Roth, 2017). These factors mean that they are not likely to take drastic measures rashly, and that they will follow an adaptive management plan in a dynamic way. It will take further years following this policy of cutting stock input to truly see the results and whether measures should be re-adjusted as it is relatively early into the action plan. Only 5 years ago the state was inputting millions of fish into the ecosystem, and have only recently seen their actions needed changing.


Management practices that can avoid conflict and proceed amongst uncertainty is critical to situations such as this. We will only continue to see issues in our lakes arise more commonly as different detrimental factors occur, invasive species being only one example. Also, the King salmon are surely not exclusive to the threat that these invasive mussels pose. Adaptive management steps are important to avoid fishery collapse from occurring in the future in the Great Lakes area in the future, not only for the ecosystem’s sake but for the local economy as well. Hesitation is not a viable option under the circumstances of resource management.

Roth, R. (2017). Lecture 11, Adaptive Management; Lecture 11: EA,  (Powerpoint slides)

The associated Press. (2017). Future of king salmon uncertain in Great Lakes. CTV News. Retrieved from:

About the author