Lesson Plan

How Many Salmon Are Enough?

brown bear holding a red colored salmon in its mouth
Salmon face predation by grizzlies, and harvest by humans. How many must escape these challenges to ensure a healthy fish population?

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Grade Level:
Ninth Grade-Twelfth Grade
Biology: Animals, Conservation, Earth Science, Engineering, Marine Biology, Mathematics, Statistics, Wildlife Management
3 in-class periods (50 minutes each) plus at home research
National/State Standards:
NGSS HS-LS2: Use mathematical representations to support and revise explanations based on evidence about factors affecting biodiversity and populations in ecosystems of different scales

salmon, ecosystem, ecology, Trends, graphing, Data, Statistics


Use this lesson to explore ecology, biodiversity and populations. This lesson takes real life experiences and scientific data to connect with students at a personal level and achieve a greater understanding in how wildlife and humans are connected.


  • Students will be able to calculate rates of escapement of salmon and draw conclusions based on population trends.
  • Students will be able to compare different sets of data based on graphs.
  • Students will be able to explain the importance of maintaining a balance in the environment and show the importance of individuals within an ecosystem.


Lake Clark National Park and Preserve is a major spawning ground for the sockeye salmon. Park biologists study salmon populations in the Newhalen River.

Over thirty years of data from that study helps us understand the reasons salmon are so important to Alaska's ecosystem. This lesson allows students to relate to the ecosystem in which these salmon live. In the process, this lesson ties into a study of human impacts on the natural world, as well as the idea of resource management.

This lesson will take several periods to complete, with additional out of class time required to work on an assessment piece. It is a cross-curricular activity that ties in math, history, and science. Students will create graphs, analyze trends, and make calculations based on data. Students will analyze raw and studied data from the Newhalen River and other rivers or bays to determine trends and the effects of changes to environments. They will also conduct research to find historical data, which they will analyze to identify trends. The lesson can be altered to accommodate the level of the students, the focus of the class, and the area of study.




Students should use the information from Telaquana Weir escapement project and analyze it for trends. Students will show graphs, their reasons for decisions on the trends, and a comparison to the Newhalen River information they have already analyzed.

Park Connections

Salmon are one of the most vital resources at Lake Clark National Park and Preserve. Several on-going studies investigate why salmon move to certain spawning grounds, how long it takes to get there, and how many fish are spawning in certain areas. These studies inform an index that allows the public and park staff to monitor the number of fish in the river, and to track their movements.



Interested teachers and classes can explore this topic further by creating their own counting towers or locations. For example, students might engineer a mechanism to count salmon and give accurate numbers. This would also address Next Generation Science Standard ETS1 (engineering design). If a teacher is interested, they could seek to connect this to an exploration of watersheds or genetic variation. Teachers could consider asking a scientist come to the classroom to speak.


Ecosystem, Resilience, Escapement, Natural System

Last updated: December 15, 2017