Before the lesson, cover any grooves around the edges of the trays.
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:
Drawings of K’ómoks fish trap designs in the Comox harbour on Vancouver Island: https://hakaimagazine.com/wp-content/uploads/shapes2-fish-trap-people.p…
Wooden poles, made from Douglas Fir saplings, are pounded into the sand, in a shape that direct fish into the trap. These poles remain year round. Woven panels are lashed to the poles when the trap is in use.
Article on pole remains in Comox harbour, video of fish being trapped, and more information at https://hakaimagazine.com/features/the-ingenious-ancient-technology-con…
