Human Impacts—How Many Fish?

Summary: How many fish do humans harvest, and can we harvest as many as we can and still expect fish populations to remain stable over time? Through hands-on modeling activities, students explore issues of population ecology and stock management issues in the Pacific Northwest. All of the activities presented here lead to stewardship activities that are listed in the Finding a Balance topic guide.

Concepts to teach: Renewable and non-renewable resources, population ecology, fisheries management, sustainability

Goals: The ocean’s resources are vast but not unlimited. With the help of scientific research and modeling, fisheries managers make rules about fishing so that the industry will remain (or become) sustainable.

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S7.2E.1, S7.3S.1

Specific Objectives:

  1. Recognize that fish populations remain stable when life history characteristics, ecological relationships, and harvesting practices are in balance.
  2. Explain how technology changes success in fishing.
  3. Demonstrate how fisheries managers use scientific research, models, and math to determine how many fish can be harvested.

Activity Links and Resources:

  • Use the NOAA Fisheries: Office of Science and Technology website to download actual data on fish caught from year to year. The site allows you to sort for a specific species such as “salmon, sockeye” and for a location, “Oregon.” Use the data for graphing, finding mean and median, comparing, and other math exercises.
  • NOAA Fisheries Northwest Regional Office School Curricula highlight how scientific evidence and stakeholder input help NOAA Fisheries policy makers and manager to decide on regulations and other actions to conserve and manage the resources for which the agency is responsible.
    • Sustainable Halibut Fisheries
      • Lesson 1—Halibut life history, anatomy and adaptations
      • Lesson 2—Sustainability, technology changes
      • Lesson 3—Data collection and analysis, Halibut Derby activity
  • One Fish, Two Fish—Designed by OIMB Graduate students, this lesson encourages students to find a balance in their fishing practices.
  • Empty Oceans—This lesson plan from National Marine Sanctuaries focuses on how humans affect seafood species populations.


  • Assessment worksheets and other tools are included in the NOAA Fisheries curricula.