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Salmon Connections: Estuary

In this game, students simulate the challenges that salmon face as they move into and out of the estuary.

Estuaries are formed where fresh water from rivers and streams runs off and mixes with saltwater from oceans. Any plant or animal that lives within this environment must be tolerant to a wide variety of conditions such as low and high salt concentrations and hot and cold temperatures.

Most Pacific salmon are born in fresh water, spend their adult lives (1-2 years) in saltwater oceans and then return to their natal rivers (the rivers they were born in) or lakes to spawn.

Many animals rely on salmon passing through the estuary for food. Examples include: river otters, seal, bears, wolves, ravens, gulls, eagles and people. 

Objectives

  • List a variety of organisms which live in the marine and estuarine environment and identify feeding relationships as a connection between them.

  • Identify Salmon as a “keystone species” and explain why.

  • List and describe human impacts on ocean environments.

Materials

  • Per Class or Group:
    predator tags or pinnies (great blue heron, gull, river otter, bear, bald eagle, wolf, seal, fisherman)
    large open space (field or gym)
    small items to represent food (cards, paper, or cardboard would work)

Key Questions

  • Salmon fry are small (4-6cm). Is it hard for predators to see them?
  • How do salmon survive in a changing environment (freshwater to saltwater and vice versa?)
  • In which environment do salmon grow the most?
  • Where do they spend most of their life?

What To Do

Teacher Tip: To ensure smooth game play, walk the students through the roles and rules of the game to ensure that each knows what to do and where to go before you start.

Set-up: Identify three areas in the open space as spawning grounds, estuary and ocean.

​Game: 

  1. Choose three students to be river/estuary predators (great blue heron, gull and river otter) and give them predator name tags.
  2. Designate all remaining students as salmon and have them start in the spawning grounds, crouched down as eggs.
  3. Have the students stand up to represent hatching. They are now alevins in the gravel with big potbellies filled with nutritious yolk.
  4. Have the students start to slowly move around, to represent that they have finished the nutrients in their yolk sac and that they are finding food (insects) and swimming through the river as salmon fry.
  5. On a signal, the salmon students run downriver from the spawning grounds to the estuary. Predators chase the salmon as they run.
  6. Any salmon that are caught become river/estuary predators (bear, wolf, bald eagle, etc) and chase the salmon as they run the next leg of the journey from the estuary to the ocean.
  7. Salmon that are caught on the way to the ocean become ocean predators like orcas or fishers. Fishers may link arms to catch salmon in a net.
  8. Surviving salmon students are now adult salmon and must return to their home stream to spawn. Salmon students must run back from the ocean to the estuary (avoiding predators), and then run to the spawning grounds (avoiding predators).
  9. Once the final salmon students reach the river, the game is over. Let the students know that in reality up to 90 per cent of the salmon that hatch never make it back to their spawning grounds.

Extensions

  • Around estuaries, salmon carcasses are brought into the forest by predators. When they breakdown, they fertilize the soil in the area. Discuss the importance of this complex food web that connects the terrestrial ecosystem with the marine ecosystem .

Other Resources

Great Bear Sea | Elementary Resources | Secondary Resources

Fisheries and Oceans Canada | Stream to Sea K-12 Education

Pacific Salmon Foundation | Salish Sea Salmon Education Booklet

Government of Canada | Fisheries and Oceans | Salmon