Eel Life Cycle Exploration

Te Ao Pūtaiao — Living World

Name:

Date:

🎯 WALT & Success Criteria

WALT: Explain the life cycle of the eel (tuna) and its migratory journey.

By the end of this worksheet I can:

Outline the stages of the eel life cycle in order.

Explain why eels migrate from freshwater to the ocean.

Describe the ecological and cultural importance of eels (tuna) in Aotearoa.

🐍 Part 1: The Eel Life Cycle

1. Label the stages of the eel life cycle. Use the word bank below to fill in the blanks on the diagram description.

Word Bank: egg, leptocephalus (larva), glass eel, elver, adult eel

Stage 1: _________________________ — Spawned in the ocean near Tonga.

Stage 2: _________________________ — Flat, leaf-shaped larva that drifts on ocean currents.

Stage 3: _________________________ — Transparent and small; enters freshwater rivers.

Stage 4: _________________________ — Young eel that begins to develop pigment and grow.

Stage 5: _________________________ — Lives in freshwater rivers and lakes for many years.

2. Which stage of the eel's life cycle takes place in the ocean? Circle all that apply.

Egg

Leptocephalus (larva)

Glass eel

Adult eel (tuna)

3. How long can an adult eel live in freshwater before migrating back to the ocean to spawn?

1–2 years

5–10 years

Up to 20–80 years

Over 200 years

4. Draw and label a simple diagram of the eel life cycle in the box below. Show at least 4 stages and use arrows to show the order. (Scaffolding: You may use the stage names from Question 1 to help you.)

🌊 Part 2: Migration & Importance of Tuna

5. Why do adult eels migrate from freshwater rivers back to the ocean? Explain in your own words.

6. New Zealand longfin eels (tuna) travel thousands of kilometres to spawn near Tonga in the Pacific Ocean. After spawning, what happens to the adult eel?

They return to the same river they came from.

They die after spawning.

They stay in the ocean for the rest of their lives.

They migrate to a different freshwater river.

7. Give two reasons why eels are important to freshwater ecosystems in Aotearoa New Zealand.

8. Tuna (eels) hold great significance in Māori culture. Describe one way that tuna are important to Māori. (Scaffolding: Think about food, stories/whakapapa, or kaitiakitanga — guardianship of the environment.)

9. New Zealand's longfin eel is found only in Aotearoa. Why do you think it is important to protect this species?

⭐ Challenge Question (Extension)

10. Human activities such as building dams, draining wetlands, and water pollution can affect eel populations. Choose one threat and explain: (a) how it affects the eel life cycle, and (b) what could be done to reduce this impact. Use scientific language in your answer.