Lessons: Energy

The Life Cycle of Salmonids

Respect Rule: Look, Listen, Learn, and Leave Alone (until instructed).

Overview

The life cycle of the salmonid is fascinating. The fish hatch and spend the early part of their lives in freshwater. The young salmonids stay in the river where they were born anywhere from a few months to a few years before traveling out to sea. After a period of one to three years in saltwater, the salmonids migrate back to freshwater rivers of their birthplace to breed and die. The effects of human activity have brought a decline in the salmonid population. The survival of salmonids and the observation by future generations of this valuable life-cycle depends on today’s stewardship of the riparian habitat that exists in watershed areas of the foothills.

Background

Anadromous salmonids (salmon and steelhead trout) once ranged into the Mokelumne River, Calaveras River, Tuolumne River, and Stanislaus River systems. Historically, their spawning grounds extended throughout the foothills but are now blocked by dams or other human activity. There are still opportunities to view salmonids at the beginning and the end of their life cycle, to evaluate their habitat, and to engage in projects that will draw awareness to the preservation of these wonderful creatures on the Calaveras River (Corp of Engineers at New Hogan Lake), at the Mokelumne River Hatchery (EBMUD and Dept. of Fish and Game), Knights Ferry on the Stanislaus River, and Mocassin Fish Hatchery on the Tuolumne River. They have educational opportunities that address the salmonids in rivers and streams. The best months to see salmon in the local area are October through December. Steelhead arrive later from December through March. Exact dates may vary, so call ahead before planning a field trip.

“Through interpretation, understanding.
Through understanding, appreciation.
Through appreciation, protection.”

—Betty Van Der Smissen and Oswald H. Goering,
A Leader’s Guide to Nature-Oriented Activities


Before-the-Field-Trip Activities

Activity 1: Locate the Salmonids
Time: 1–2 hours
Materials: Where Can I Go To See Salmonids? Fact Sheet and Transparency, Chart paper, markers, can of salmon, package of smoked salmon or product from salmon

  1. Discuss with the students what types of fish do people eat.
  2. List responses on chart or draw picture (tuna, bass, sardines, salmon).
  3. Show students the can of salmon. Explain salmon is one of the most popular types of fish that people in the United States eat.
  4. Sense of taste and smell can be very dramatic. Open the can and sample.
  5. Salmon is not just a food but it is an animal that leads a very interesting life! Write on chart “fresh water” and “salt water.” Discuss with students where “fresh water” fish live. Make sure responses include lake, ponds, streams, and rivers.
  6. Discuss with the students where “salt water” fish live (ocean).
  7. Discuss with students where fish can be seen (lakes, rivers, oceans, etc.)
  8. Continue the discussion:
    Has anyone ever had a fish as a pet?
    Was the water you put into the aquarium salty or “fresh” (like the water you drink)?
    Can fish live in salty water?
    Some fish like salty water and some fish like fresh water. Salmon and steelhead trout are very special because they like both fresh and salty water.
  9. Distribute the Where Can I Go to See Salmonids Student Worksheet and discuss: Which part of the Pacific Coast do salmonids live? Students should recognize this is a map of the Northwestern part of the United States. Some salmonids live in the Atlantic Ocean but their range is not shown on this map.
  10. Locate the local hatchery.
  11. Explain that all the locations shown on the map are sites where salmonids come to spawn or finish out their life and where new salmonids are hatched to continue the cycle. Have students note the neighboring states that have salmonids.
  12. Draw rivers leading to the hatcheries.
  13. Examine maps carefully. Do the salmonids stay in the ocean or do they go inland? Explain that salmonids spend much of their lives in rivers and streams that may be hundreds of miles from the ocean.

Activity 2: Life Cycle of the Salmonids
Time: 1 hour
Materials: The Saga of the Salmonid Fact Sheet, Salmonid Life Cycle Fact Sheet, slides of the life cycle of salmonid (available through STE Lending Library)

  1. Read the Saga of the Salmonid Fact Sheet.
  2. Discuss the life cycle stages of the salmonid using Salmonid Life Cycle Fact Sheet.
  3. Review the key concepts and words.
    • Eggs—salmonids lay their eggs in gravel in the streams.
    • Alevins—salmonids hatchlings (Notice the yolk sacs. Alevins stay in the gravel. They get food from their yolk sacs and grow bigger.)
    • Fry—baby fish. After the yolk sac is gone, the baby fish swim out of the gravel and eat insects and other food.
    • Smolt—fry that is 1–3 years old (orange salmonids). They swim down the river (migrate) toward the sea. The smolt spends time in the estuary (mouth of river meeting the ocean) getting ready to go out to sea.
    • Adult salmonids—When the salmonid arrive at the ocean they eat a great deal to get ready for their journey home. They also swim very long distances. Some salmonid swim up to 10,000 miles. They stay in the ocean for a few years. But when it is time to spawn, the most amazing thing occurs: they are able to find the very same river or stream where they were born! Scientists believe it is the smell of the water that allows this to take place. It is sometimes a long and hard journey. They may have to leap up high waterfalls or fight strong currents.
    • Spawners—adult salmonids that lay their eggs and then die. The dead fish revitalize the streams and rivers with nutrients and feed river animals. Nature’s beautiful cycle of life continues.

Field Trip Activity

Activity: Tour a Hatchery
Time: 1½ hours

  1. Take students on a tour of a fish hatchery or trout farm.
  2. Discuss the life cycle and different kinds of salmonids, raising fry, spawning room, and the harvesting of the eggs.

After-the-Field-Trip Activity

Activity: Life Cycle Activities
Time: 45 minutes
Materials: Newspapers, paint, string; Pacific Salmon and Steelhead Coloring Book and Salmonid Savers, Sal­mon Boy told by Joseph Bruchac, and Come Back Salmon by Molly Cone book and video (available from the STE Lending Library)

  1. Students can create life-cycle mobiles of the salmonid to better understand habitat requirements at all stages of life for anadromous fish. Use newspapers to stuff 3-D, life-sized drawings of the salmonids.
  2. Review and color The Pacific Salmon and Steelhead Coloring Book and the Salmonid Savers.
  3. Read Salmon Boy.
  4. View and read Come Back Salmon.

Objectives

Students will realize that the salmon faces a unique set of challenges in its life cycle and the struggle to live, mature, spawn and die.

Grade Levels

K–4

Adult/Student Ratio

1 to 20

Location

Riparian habitat: creeks, streams, rivers, school sites,
utility facilities: sewers and water treatment plants, dams, hatcheries

Skills

Sequencing, observing, recording, making connections

Key Words

Salmonid, Alevin, Fry, Buttoning up, Smolt, Milt, Estuary, Yolk sac, Spawn

Downloads [PDF]

Resources

For the Teacher

  • US Department of Fish and Game
  • US Fish and Wildlife Service
  • US Core of Engineers
  • Trout Unlimited and Fly Fishers
  • Water Education Foundation, Sacramento, CA
  • US Forest Service

For the Student

  • The Pacific Salmon and Steelhead Coloring Book, US Fish & Wildlife Service
  • Come Back Salmon, Molly Cone (book or video)
  • Salmon Boy, a Tlingit tale from Flying with the Eagle Racing the Great Bear, Joseph Bruchac.
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