Fish trap model

Use playdough and a marble in a tray, to understand how a fish trap works.
Science content
Biology: Indigenous People's sustainable use of Living Things (K, 2, 3)
Earth/Space: Indigenous People’s Traditions around Sky, Land and Seasons (K-7)
    per student:
  • shallow white tray e.g. IKEA
  • ball of play dough
  • marble

Describe how Coast Salish Indigenous people, and people around the world traditionally and today, make traps in rivers to catch fish. They are a sustainable way of catching fish.
They are used seasonally, when fish are migrating up rivers, or built on mud flats to hold fish when the tide goes out.

Fish traps in rivers are placed where adult fish return upriver to spawn. Fish traps are made of rocks or woven mats, and guide the fish through a maze of walls and compartments, and since migrating fish tend to move ahead and rarely turn backward, they end up in compartments that they cannot escape from. People wade into the river and use a net or spear to catch the fish from the trap.
Fish traps are sustainable, as the fish are not damaged in the trap, and fish that are unwanted can be released back into the main river (gill nets or seines damage fish as they become wedged and lose scales).

Demonstrate the activity to students, before giving them their own materials.
The marble is a fish, and rolls around the tray, like a fish swimming in a river.
Roll the play dough into sausages and stick them to the bottom of the tray, to make shapes that will trap the rolling marble.
By forming passages with the play dough that funnel the marble to one end of the tray, but have a narrow opening which makes it hard for the marble to roll back, the model shows how fish traps work.

Either before or after the activity, show students photographs/videos of fish traps:
Photos of Squamish First Nation fish traps made from rocks on the Capilano River: abd…
Video of a fish trap made from rocks by Alaskan Inuit, with explanation of how it is repaired and used, within a 15 minute story.
Photo of an Alaskan fish trap made from wooden stakes, with woven mats below the water line:
Drawings and photos of a K’ómoks fish trap in the Comox valley, showing remains of the wooden poles.… Video and more information at… Poles, made from Douglas Fir saplings, pounded into the sand, in a shape that direct fish into the trap. These poles remain year round. Woven panels were lashed to the poles when the trap is in use.

Grades taught
Gr K
Gr 3
Gr 4