Subject

Life Science

 

Objectives

In this lesson the students will learn about the salmon life cycle, and their habitat for each stage in the life cycle.

 

Materials

• Life Cycle Slideshow
• Art supplies – crayons, markers, or pencils
• Life Cycle Wheel
  • Sourced from: Nooksack Salmon Enhancement Association

 

Background

There are five species of pacific salmon, Chum, Coho, Pink, Sockeye, and Chinook. Salmon are anadromous fish, this means that they are born in freshwater, spend most of their life in the ocean, and return to the freshwater to spawn. There is also one species of anadromous trout (Steelhead) that have a similar life cycle as pacific salmon.

Spawning salmon travel up the watershed to the river in which they hatched. The female salmon will lay about 3,000 eggs in the stream bed after creating a redd (salmon nest) by using her tail, this will help protect the eggs from predators and sunlight. The male spawning salmon will release their milt to fertilize the eggs. The fertilized eggs will take two to four months to hatch. Once these eggs hatch the salmon are now alevin. Salmon in this stage get their nutrients from their yolk sac and continue to live in the freshwater stream that they hatched in. It is very important for these streams to have clean, cold and clear water in order for the salmon to survive.

Once the yolk sac has been absorbed the salmon are now fry. Fry eat mostly macroinvertebrates in the stream bed. Some fry remain in the streams for a small amount of time (Chum and pink) and some will spend up to a year in the stream as fry (Chinook, Coho, sockeye).

The next stage of the salmon life cycle is smolt. This is the stage that the salmon live in an estuary, where the river meets the ocean, to start the smoltification process, the process to help them transfer from freshwater to saltwater. The salmon will spend 1-3 months here before becoming adults and spending the next 1-9 years in the ocean. In the ocean adult salmon will eat zooplankton, shrimp, and small fish while they grow and mature into spawners.

Spawners are salmon that have matured completely and begin their migration back to the stream they hatched in. During this migration salmon do not eat, and they use their sense of smell to find their way home to spawn. Once the salmon has spawned, it will die and begin to nourish the ecosystem. From the trees and flowers to bears and bugs, the salmon are used as nutrients to keep the ecosystem healthy.

 

Procedure

1. Talk about the human life cycle.
   1. We start out as babies, then toddlers, then kids, teenagers, and adults.
2. Go through the Life Cycle Slideshow and walk the kids through the life cycles of other plants/ animals.
3. Once you get to the salmon life cycle part of the slideshow walk them through their habitat and life cycle stages for them to fill in their life cycle printout.