Lesson Title: Nechako White Sturgeon – our local gentle giant
Subject: Science
Grade: Intermediate Elementary Duration: 1.5 - 2 hrs
Rationale: The purpose of this lesson is to provide the students with an overview of the
Nechako white sturgeon and the challenges it currently faces. The goal is to have
students be aware of local issues in order to connect to the Nechako watershed.
Prescribed Learning Outcome(s): It is expected that students will…
Grade 4 LS (Life Science):
Grade 5 ESS (Earth and Space Science):
Grade 6 (LS):
Grade 7 (LS):
Compare the structures and behaviours of local animals and
plants in different habitats and communities.
Analyse simple food chains
Determine how personal choices and actions have
environmental consequences.
Describe potential environmental impacts of using BC’s living
and non-living resources
Analyse how different organisms adapt to their environment
Analyse the roles of organisms as part of interconnected food
webs, populations, communities, and ecosystems
Assess survival needs and interactions between organisms and
the environment
Assess the requirements for sustaining healthy local ecosystems
Evaluate human impacts on local ecosystems
Instructional Objective(s): To explain what losing the endangered Nechako white
sturgeon would mean to the individual student.
Prerequisite Concepts and Skills: It would benefit students if they know of the Nechako
river and that the Nechako white sturgeon is one of the most unique and prehistoric
creatures found in it.
Materials and Resources:
Teacher
Students
Large Visual /Model of the White Sturgeon
Map(s) of Nechako Watershed
White Sturgeon – Species at Risk, a publication by Fisheries
and Oceans Canada. 2008
Hatchery Staff in Class Presentation (Kootenay Trout
Hatchery)
Upper Columbia White Sturgeon Elementary resource Kit
Pens
Paper
Markers
Computers and/or science journals
Information about various stages in the sturgeon’s life:
http://uppercolumbiasturgeon.org/Tours/TourBiology1.html
Extensions:
Book
Appendices
Art materials
Lesson Activities:
Teacher Activities
Student Activities
Introduction (anticipatory set): 5 - 10 min
A large visual (or model or plush toy) of the White sturgeon is displayed.
The class talks about what they already know about this gentle giant.
Body: 1 – 1.5 hr
Students are invited to view the model or
visual of the sturgeon, discuss it, while
recalling and gaining new background
knowledge.
History:
Briefly talk about the tremendous history of the white sturgeon:
Cool fact:
This largest freshwater fish in North America has lived for more than 250 million years
and the Nechako white sturgeon species for 7-9 million years
Through adaptations, white sturgeon are very well adapted to the cold, dark, deep
rivers and lakes they live in.
Students look at the map and
participate in discussion.
(show map of Nechako watershed)!
Ask:
Why do we care so much about the sturgeon? (Because it is endangered).
What does endangered mean?
(Refer to the Endangered Species Handout)
What caused the species to become endangered?
(Overfishing, introduction of exotic species, dikes and drainage projects, industrial
and municipal pollution and hydroelectric dam building: block access to spawning
sites, eliminate spring flooding, trap nutrients on which salmon depend, reduce
downstream turbidity so that juveniles are more visible)
Anatomy:
(Refer to the External Anatomy Functions Worksheet for more information)
Look at the large model.
Interesting fact:
The sturgeon has remained relatively unchanged for millions of years.
Point out and discuss the external features of the sturgeon: what is different with this
gentle giant? (No scales but denticles, torpedo-like body (bottom rover) with dorsal
fin, 5 rows super sharp bony plates – scutes, 4 barbels to detect foods, wide toothless
mouth…).
While the different external parts of the sturgeon are taught to/explored with the
students, the functions of the body parts are also discussed (for example: denticles to
move faster in water and to protect themselves; the body shape and mouth makes it
ideally suited for bottom feeding; scutes are for protection especially during the
juvenile stage; the 4 barbels help sturgeon detect food at night or in murky waters;
and the mouth has no teeth but expands outward, because the sturgeon feeds by
sucking in the food from lake or river bottom).
Discuss the possible size (length: up to 6m and weight up to 635 kg) of the sturgeon
and challenge students to find things in the classroom that are as long or heavy.
Students are invited to explore and
discuss the external structure and
features of the sturgeon.
Life cycle:
Show visual/poster of life cycle.
Eggs: Spawning sites are deep and have faster currents and rockier bottoms than
normal foraging habitats. Small, sticky eggs are released over large areas of riverbed
where eggs stick to the rocky bottom (known as broadcast spawning). Eggs and
sperm from male sturgeon are well mixed by the strong currents. 5 – 25 days (longer
time when temperature is lower)
Students learn about the various stages
of the sturgeon’s life cycle. They are
invited to ask questions and interact
using the visuals provided.
Students can possibly draw or sketch the
life cycle in their science journals.
3 cool facts: A single female can produce several million eggs but they do not spawn
every year. And, if the conditions are unfavourable, the female will reabsorb her eggs
and not spawn that year. SPAWNING SITE in the Nechako watershed: in the Nechako
river by the bridge in Vanderhoof (Burrard Avenue).
Larvae: The hiding larvae have the yolk sac attached and they hide within the rocks.
When the yolk sac is used up (feeding larvae), they begin to feed on macro organisms
(insects and zooplankton) and begin to drift downstream (to feed and avoid
predators to locate hiding places) with the current for many kilometres.
Juvenile: 40 days (at this stage they look complete with a full set of scutes and fins) –
sub adult. They can be selective in their choice of foods but tend to eat benthic
invertebrates and fish
Age 5: 50 cm.
Comment: The survival rate is very low in the first year of a white sturgeon’s life, even
under optimum conditions!
Sub-adult: Near adult sturgeon, not mature. They are capable of consuming large
prey including adult salmon
Age 5-25: Grow 5 cm /year. Then growth slows down.
Sexual maturity for males: 20-25 years old. Females: 15-30 years, spawn at intervals of
up to 10 years and deposit a million or more eggs in a single spawning.
Sturgeon can live to become more than 100 years old.
Habitat:
What is needed in the sturgeon’s habitat that would meet its needs?
1. Clean water
2. food
3. shelter
4. clean gravel for spawning
Use map of the Nechako watershed.
They can find water anywhere in the Nechako Watershed. However, the
characteristics of water needed vary depending on the life stage of the Nechako
white sturgeon.
a) Spawning: deep, rocks, turbulent and clean water
b) Larvae and juvenile: hiding places, turbulence, lots of feeding
opportunities (eat more of a variety of food)
c) Adult: on the bottom of deep and dark waters for feeding (follows
the salmon) and wintering. See a) for spawning
Cool Fact:
Counter shading: When a fish is dark on top and light below. To a fish swimming above
the sturgeon, the sturgeon blends into the waters dark depths. To a fish swimming
below the sturgeon, it blends into the light filtering through the water above.
Students locate the various spots of the
Nechako white sturgeon’s habitat on the
map of the Nechako watershed.
The Nechako white sturgeon live in a few large, productive lakes such as the Stuart
Lake and Fraser Lake.
Students think of the questions, discuss
them with a partner and participate in
group/class discussions.
In the last 60 – 100 years (a minimal amount of time compared to how long sturgeon
has been around), the sturgeon population is declining severely. Explore the following
questions:
- How has habitat changed (look at 1964-67 when recruitment declined severely)? - --- What are the reasons? (Human impact: building dams/ flow regulation (natural
events due to this such as the Cheslatta avulsions), diking and drainage projects, overfishing, dwindling food resources, and urbanization (declining water quality, but this is
still being studied).
- What is being done (restoration projects and initiatives and what more can be
done?
The students reflect either orally with a
partner or write in their journals.
Ensure that arguments and findings are backed up with relevant arguments and
evidence.
Closure: 10 – 20 min
The teacher tells the student:
Reflect on what the decline of the Nechako white sturgeon means to you. If it was to
become extinct, what have we lost?
Organizational and/or Behavioural Management Strategies: Students are encouraged
to discuss, reflect, and participate throughout the lesson. By engaging them, the teacher
minimizes opportunities for behaviour issues.
Assessment and Evaluation: The formative assessment is observation throughout the
lesson to ensure students are gaining an awareness of the Nechako white sturgeon. The
summative assessment is clipboard cruising if the students are sharing orally with a
partner, or reading their science journals after the students have written their reflections.
Extensions:
Read Tale of a Great White Fish by Maggie DeVries
Go for a nature walk to a spot in the Nechako watershed and discuss sturgeon activity:
Burns Lake: Opportunity to visit other town sites that are important for the Nechako white
sturgeon
Fort Fraser: feeding
Fort St James: feeding, wintering
Fraser Lake: feeding and wintering
Vanderhoof: spawning
Complete attached worksheets and/or activities (Appendix)
Continue with lesson about riparian zones to provide deeper understanding about the
Nechako watershed.