Fish Finders
Students explore the needs of salmon at each stage of their life cycle and then go on a field trip to investigate a local aquatic habitat and its potential as a salmon habitat. They observe the physical characteristics of the stream and argue from evidence whether or not salmon could survive well there. Extensions are included to gather additional evidence by measuring the water quality parameters of water temperatures, dissolved oxygen, and pH; measuring stream velocity, and collecting and identifying macroinvertebrates as indicators of water quality.
Essential Question(s)
How do different organisms meet their needs and survive more or less well in a particular place under a particular set of environmental conditions?
How do differences in environmental conditions affect the survival of salmon?
PDF Investigation
Time Required
4 class periods
Life Sciences
Investigation Type
Field Trip, Classroom
Grade Level
NGSS Performance Expectations
Materials Needed

 Field Equipment:

  • Thermometer (one per group) on a string so it can be submerged in water
  • D-net (one at a station or per group) and fine mesh nets (several) to capture macroinvertebrates
  • Macroinvertebrate Identification Key and Macroinvertebrate Indicator diagram
  • Trays or ice cube trays to observe and sort macroinvertebrates
  • Pipettes, hand lenses and large tweezers
  • Digital camera (one per group)
  • Pencils (one per student)
  • Clipboards (one per student)

Optional: Additional water quality testing equipment and supplies for student investigations to collect evidence whether or not habitat conditions meet salmon needs for survival. (See lesson plans linked to Extension for more specific information.)

  • Dissolved Oxygen: Dissolved oxygen test kits or meter, stopwatch
  • ph: pH paper, test kits, or meter
  • Stream velocity: Stopwatch, 100’ long rope, and rubber ducky or block of wood

NGSS Performance Expectation

Students who demonstrate understanding can:

Construct an argument with evidence that in a particular habitat some organisms can survive well, some survive less well, and some cannot survive at all. (3-LS4-3)


Knowledge - Students will know that:
  • what salmon need at each life stage
  • that different habitats meet the needs of different organisms to different degrees
  • for any particular environment, some kinds of organisms survive well, some survive less well, and some cannot survive at all.
Skills - Students will be able to:
  • measure water temperatures (and other physical and chemical characteristics of a stream with the extension activities)
  • observe habitat characteristics
  • construct an argument from evidence
Local and Cultural Connections
Salmon are important to Alaskan communities, cultures, and economies. The majority of Alaska schools have a salmon stream within walking distance or a short bus-ride away.

Invite local fisheries biologists from state and federal agencies and experienced local participants in subsistence, recreational, and commercial salmon harvests to your classroom or as guides and instructors for stream field trips. Ask fisheries biologists or knowledgeable local people about places where students can observe human activities that affect salmon streams – both negatively (Examples: a poorly-placed culvert that blocks migration, pollution from poorly planned land use practices or development, removal of riparian habitat next to the stream) or positively (Examples: a salmon habitat restoration project, a fish ladder). Field trips could also be planned to local seafood processing plants or hatcheries.
Teacher Preparation

Make copies of science notebooks and hand-outs. (See Science Notebook Example Pages) Locate a watershed map for the field trip site (can often be inferred from an online map that shows topography in relation to stream channels and water bodies).

Find a local aquatic habitat for the field trip. It may be a stream, lake, estuary, or another area that might provide habitat for fish. Visit site to determine the boundaries of your investigation, and to get ideas for student investigation. What should they notice? Identify another location for a station where salmon are not likely to survive.

Set a date and take care of logistics for the field trip: permission slips, parent volunteers/chaperones, transportation, snacks, water, restroom facilities, etc.

Learning Experiences


(30-45 min.)

Ask students to recall the stages of a salmon’s life cycle. Write the stages (eggs, alevin, fry, smolt, adult, spawner) as headings on the board, then write “need” after each one and have students list the basic needs for each life cycle state. You may also provide a blank Salmon Needs Chart for students to complete. They can glue the completed chart into their Science Notebook as a reference on the field trip. You can also print out the 11” X 17” Salmon Life Cycle Poster and put it up on the wall during this discussion.

Introduce the term “habitat” and remind students that habitat includes food, air, water and shelter arranged in a certain way. To help prompt students for responses, you might ask them to answer the following questions about each stage:

  • Where does it live (fresh water or salt water)?
  • Does it have special needs to live here? (shelter - gravel, rocks, plants, for protection)
  • What dangers are present at this life stage? (predators, human impacts)
  • What does it eat?
  • What is special about it at this stage that allows it to live in the place that it does?
  • Are there any other interesting facts that should be noted at this stage?

If students don’t mention air as a need, this is a good time to discuss the concept of oxygen in the water. Salmon need water that is rich in oxygen to remain healthy, especially in the life cycle stages that take place in freshwater. Water that moved rapidly across rocks and boulders causes the air to mix with the water and plants in the water take in carbon dioxide and “breathe” out oxygen after they make their own food. The salmon, like all other animals, need oxygen and they take it in as a dissolved gas through their gills.

Students can do research using resources in the Resources section and re-visit the chart to continue filling it out. Emphasize the “3Cs” (cold water, clean water, all habitats needed for a complete salmon life cycle connected within the watershed and to the ocean) if they don’t come out during the discussion.

Your completed chart may look similar to this.

Salmon Needs Chart

Life Stages




  • Freshwater
  • Gravel to incubate in
  • No food necessary
  • Clean, clear, cold water
  • Birds, small mammals
  • Floodwater
  • Disease
  • Freezing
  • Pollution
  • Too much mud and silt in the stream


  • Freshwater
  • Gravel to hide in
  • No food necessary (feeds on yolk)
  • Clean, clear, cold water
  • Birds, bigger fish, aquatic insects
  • Disease
  • Pollution
  • Too much mud and silt in the stream


  • Freshwater
  • Rocks and plants to hide in, under or around
  • Places where the current is not too strong to sweep them downstream
  • Bigger fish, birds
  • Pollution
  • Floods


  • No blockages to migration from the stream to the ocean
  • A place to slowly adjust to living in salt water
  • Smaller fish and plankton for food
  • Clean, clear, cold water on the way to the ocean
  • Dams
  • Floods
  • Bigger fish, birds, marine


  • Saltwater
  • Fish, plankton
  • Bigger fish, marine mammals
  • Eagles
  • Fishing nets or hooks


  • Fresh water
  • Gravel to lay eggs
  • No food necessary
  • No blockage of the migration path from the ocean to the spawning grounds
  • Bears and other mammals
  • Eagles, gulls
  • Fishing nets and hooks
  • Dams
  • Falls or other places in the stream that are too steep to jump (e.g., where a culvert is “perched.”)
  • Pollution

Pose the focus question: “Do you think our local stream and watershed have what salmon need to survive during every stage of their life?” Ask students to write this focus question and their predictions in their science notebooks.

Ask students: How can we find out if our stream and watershed have what salmon need to survive during every stage of their life?


(30 min plus 2-3 hours for field trip)

Tell students that they will be taking a field trip to investigate a local body of water (stream, lake, or estuary) to decide if that particular location in the watershed can support salmon. Review the Salmon Needs Chart created in the previous activity. Choose to discuss or use the chart to record their findings. They can circle the items that they can see are present and cross off ones that are not. In the case of predators, allow them to circle the animals they know live in the area and eat salmon even if they don’t actually see them on their field trip. The last column is for them to record any additional observations or notes about the water or the area surrounding it.

Additionally, you may want to distribute the Water Investigation Worksheet (with clipboards and pencils) and have students answer the following questions in each rotation:

Nursery Area for Egg, Alevin and Fry

  • Are there places under the banks where young salmon could hide?
  • Is the water cold and moving?
  • Can you see any insects on the bottom of the stream, in the stream, or flying in the air?

Spawning Areas

  • Is the water clear? Can you see the bottom?
  • Is the bottom of the stream gravel (rocks the size of a pea)?
  • Is the water deep enough over the gravel that an adult salmon could swim there?
  • Is the water cold?
  • Is the water moving?
  • Would the salmon be able to come up the stream to this place without running out of water, reaching a waterfall they can’t jump over, or be encountering lots of garbage?

Field Trip Preparation:

Provide the students an opportunity to try out the field equipment they will be using, either in the classroom or outside on the playground.

Students will want to go into the water, so be sure they are dressed warmly and bring waterproof boots if they have them. If there is any danger of pollution that could cause health problems (e.g., E. coli bacteria), bring rubber gloves to use when handling the water samples.

If there are several parent volunteers, divide students into working groups for the field trip, and have them investigate different areas of the water body. Or, if there is enough time, each group can rotate through several areas of a water body, or perhaps more than one location. Choose locations with a variety of stream, lake, or estuary features in order to keep students thinking about the needs and the difficulties salmon may have living in those different locations. If possible, choose one location where salmon could not survive (e.g., polluted area, low oxygen area) or complete their migration (e.g., perched culvert), or at least note that salmon at some stages could not survive in each location. Ask your local Alaska Department of Fish and Game fisheries biologist if there are any examples of places where people have taken care to maintain salmon habitat despite the decision to develop an area or where salmon habitat has been restored. Before going on the field trip, remember to review field trip etiquette and beach etiquette with the students (and with parent volunteers).

Upon arrival at the field site, give students several minutes to explore their surroundings and notice everything that they can about the site - take note of any dangers to salmon (predators or human impacts). When necessary, have students use their Salmon Needs Chart as they are in the field to remember the needs and dangers. Have a brief discussion about this particular body of water and how it fits into the bigger local watershed.

Circulate among groups (or instruct your volunteers to supervise, and support when needed) as students work on their investigation and assist each group in taking the temperature of the water and filling out their Water Investigation Worksheet. A D-net and small mesh nets can be used to dip into the water to check for evidence of aquatic insects/macroinvertebrates as food for young salmon. Take several digital photos to document student observations.


(40 min.)

Upon return to the classroom, have students meet in small groups, paste their data sheets into their science notebooks (if necessary) and share their notes from the field trip.

Ask the groups to decide if their evidence leads them to the conclusion that salmon habitat COULD or COULD NOT survive well in the study area (or each location within it), and if so, for which life cycle stage of salmon.

Give a specific format for a science notebook entry that guides students to make an evidence-based statement for each location, such as:

Based on ________________, _________________ and ___________________ we conclude that _________________ could/could not survive well in this location.


Based on _____________________ we conclude that _______________ could/could not survive well in this location because _____________________.

These statements might be accompanied by a section, “We recommend additional study to answer the following questions…”

Ask students to reflect and comment on the importance of the study area to salmon and the watershed as a whole. Prompt students to share any human impacts they noticed that could make it difficult for salmon to complete their life cycle in the watershed.


(30 min.)

Have each student or group create a Google Slide presentation with their findings and photos. They may do a presentation in the classroom to share their knowledge and ask questions of each other.

Additionally, have students determine what could happen to change these habitats from a place where salmon to survive well to one where they would survive less well or not be able to survive at all. (This could be the result of a natural cause or a human impact. Allow students to determine how they could prevent these changes or what they can do to restore the habitat.) Students should add these thoughts and reflections to their science notebooks or presentations.


See the Science Notebook Pages Stream Field Trip for use with these extension activities.
Bio Bingo:
See the Science Notebook Example Page to create a biodiversity survey.

Human Impact Checklist: Use the Science Notebook Page as a template to customize this for what students are likely to observe on their field trip. Include activities that might make it more difficult for salmon to survive well and others that might help them.

The Science Notebook Pages include datasheets for each of the three station and a conclusion section involving argument from evidence.

Water Quality Testing: (20-30 mins. per station)
Set up stations for water quality testing using the protocols described in these investigations:

Station #1: Sampling Water Quality (water temperature, dissolved oxygen, and pH)
Station #2: Not Too Fast, Not Too Slow (measuring stream velocity)
Station #3: Macro-Mayhem (collecting, identifying stream macroinvertebrates as indicators of water quality)

Develop station signs that show the range of condition within which salmon survive well (or use this information during discussion back in the classroom:

Water Temperature: Salmon can survive well in streams that are just above freezing during the winter, but they must have unfrozen water with some flow that replenishes oxygen.
Dissolved Oxygen: > 8 ppm (mg/l.) of dissolved oxygen
pH: Range of 6.5 to 8.5
Velocity: The velocity of the current of water that salmon can swim against ranges from:
1 foot/second for a juvenile coho salmon to
10 feet/minute for an adult salmon.
Rocks and logs in the streams can slow currents. Juvenile salmon find shelter downstream as well as at stream edges and under banks. All life stages of salmon rest in pools, if available.

Sampling salmon: Juvenile salmon and other fish can be sampled with baited minnow traps and viewed in buckets or mini-aquaria in the field. A permit from the Alaska Department of Fish and Game (ADFG) is required to capture and hold salmon, so check with your local ADFG office to find out if there is someone locally who has a permit and could come out with your class and show students salmon. Look for local places (e.g, culverts, bridges) where adult salmon can be viewed as they return from the ocean. Actually seeing juvenile and adult salmon is the best possible evidence that salmon are surviving and completing their life cycle in the watershed.

(See the Teacher Background section below for more information about the range of conditions that salmon over which salmon survive well.)


Evaluate student science notebooks and/or presentations for accuracy and level of detail. Students should have included evidence to support their argument about whether or not salmon could or could not have survived well or at all in the places in the watershed they investigated.

Examples of arguments from evidence:

Based on the lack of gravel we observed, alevin and eggs could not survive in this location because they would not have shelter.Based on the amount of dissolved oxygen we measured and the amount of shelter we observed under banks, salmon juveniles could survive well in this location (provided it doesn’t freeze solid during winter).

#res85Macroinvertebrate Identification Key  
#res87Science Notebook Pages for a Stream Field Trip with Stations  
Related Lesson
#res102The Salmon Ecology Game   
Water Cycle
#res88Where Does Our Water Go?Alaska Seas Watersheds’ Grade 3 Investigation #2  
Salmon Life Cycle, Habitat Needs, and Human Impacts
#res89A Salmon’s Life JourneyAlaska Seas and Watersheds’ Grade 3 Investigation #3  
#res90Salmon Life Cycle CardsAlaska Seas and Watersheds  
#res91Migration Board Game  
#res92Salmon Life Cycle Poster  
#res93 Life Cycle Cards for freshwater and marine species

Alaska Seas and Watersheds (midges, mosquitoes, frogs) (crabs, sea urchins, clams)

Children’s Books
#res94SwimmerBy Shelly Gill   
#res95Life Cycle of a SalmonBy Bobbie Kalman   
#res96A King Salmon JourneyBy Debbie S. Miller and John H. Eiler   
#res97Salmon StreamBy Carol Reed-Jones   
#res98Salmon ForestBy David Suzuki and Sarah Ellis   
#res99A Salmon for SimonBy Betty Waterton   
#res100The Salmon Story(An online interactive life cycle) Alaska Department of Fish and Game  
#res101Alaska - Salmon in the Classroom incubation programAlaska Department of Fish and Game and 4 H  
Teacher Background

The ASW webinar “It Takes a Watershed . . . to Grow a Salmon” reviews the life cycles of Alaska’s five salmon species, how each species uses different parts of the watershed, salmon-human connections, and recent research about potential climate change impacts on salmon habitat. Teaching tips on use of the information in teaching Alaska Seas and Watershed units at various grade levels are included in the webinar.

For background information on freshwater invertebrates that live in streams or in ponds and more stagnant habitats, see Freshwater Invertebrates.

The habitat needs of salmon can be summed up by “the 4Cs”: cold, clean, connected, and complex. Complexity might be too abstract a concept for 3rd graders but the other “3Cs” are ones they can measure in terms of indicators.

  • Salmon are cold water fish. They prefer temperatures ranging from 42-55 degrees Fahrenheit (5.5 – 21.1 degrees Centigrade) but can survive in streams that are slightly above freezing during the winter provided there is enough stream flow that replenishes oxygen. [Alaska state water quality standards for fish are exceeded when water temperatures are higher than 13 degrees Centigrade (55.4 degrees Fahrenheit) in fish rearing areas or higher than 15 degrees Centigrade (59 degrees Fahrenheit) for spawning areas, eggs and fry incubation, and fish migration routes.]
  • Salmon require clean water that is not polluted by substances in water that are poisonous to salmon at some stage or by mud and silt that can smother eggs and alevins that are living in the gravels on the bottom of the stream or make it hard for juvenile salmon to find food or for adults to “smell” their way home.
  • Salmon need the habitats they migrate to and through to be connected. Anything that blocks their migration (e.g., development that buries or diverts salmon streams, roads or railroad berms with poorly-designed culverts, dams, landslides) can make upstream habitat inaccessible for salmon.

For additional information on using physical stream characteristics and macroinvertebrates as indicators of water quality, see this description of a Biotic Index developed for volunteer water quality monitors.

Prior Student Knowledge:
Student should:

  • Understand the water cycle (See the Alaska Seas and Watersheds’ Grade 3 Investigation #2 Where Does Our Water Go?) to play a game that teaches or reviews the water cycle.)
  • Be familiar with the salmon life cycle (See Alaska Seas and Watersheds’ Grade 3 Investigation #3 A Salmon’s Life Journey) and with local salmon predators, including people. With some lead time to obtain or make props, the Salmon Ecology Game provides a fun, engaging activity to introduce students to the salmon life cycle or provide a quick review.
  • Know what a watershed is and the location, name, and boundaries of the watershed where they will be going on their field trip.
  • Have practiced using and reading a thermometer.

Possible learner preconceptions, misconceptions and instructional clarifications:

Learner Preconception/Misconception: Students may say that salmon “breathe air.”
Instructional Clarification: Salmon use their gills to get dissolved oxygen from the water.

Learner Preconception/Misconception: Students may think that eggs and alevins need food.
Instructional Clarification: Salmon rely on their yolk sack during the egg and alevin life stages.

Learner Preconception/Misconception: Students may think that alevins live in the water column.
Instructional Clarification: Alevins live down in the gravel.

Components of Next Generation Science Standards Addressed

Science & Engineering Practices

Engaging in Argument from Evidence

Construct an argument from evidence. (3-LS4-3)

Disciplinary Core Ideas

LS4.C: Adaptation

For any particular environment, some kinds of organisms survive well, some survive less well, and some cannot survive at all.

Cross-Cutting Concepts

Cause and Effect

Cause and effect relationships are routinely identified and used to explain change.

Common Core

3.SL.4 - Report on a topic or text, tell a story, or recount an experience with appropriate facts and relevant, descriptive details, speaking clearly at an understandable pace.
RI.3.3 - Describe the relationship between a series of historical events, scientific ideas or concepts, or steps in technical procedures in a text, using language that pertains to time, sequence, and cause/effect.
MP.2. Reason abstractly and quantitatively.

Alaska Cultural Standards
E. Culturally-knowledgeable students demonstrate an awareness and appreciation of the relationships and process of interaction of all elements in the world around them.
2. Students who meet this cultural standard are able to understand the ecology and geography of the bioregion they inhabit.
Developed by Samantha Hammer, Cordova School District, and Marilyn Sigman, Alaska Sea Grant
Last Updated on
Last Updated by
Marilyn Sigman