News by Levels · Level 3 · For teachers
Teacher guide & answers
Sonar and Cameras Reveal Scale of Deep-Sea Eel Gathering
How to use these two pages
Give learners the student worksheet. It contains the story and questions, without the answers. Keep this guide for yourself. Use it to lead the activity and explain the answers afterwards.
Student worksheetA simple 15–20-minute lesson
- Before reading · 2 minutes
Show the title. Ask: “What do you think this story is about?”
- Read and answer · 8–10 minutes
Give out the student worksheet. Learners read for the main idea, then reread to answer the 3 questions. They can compare answers with a partner.
- Discuss and write · 5–8 minutes
Check the answers below together. Ask learners to point to the clue in the story, then finish with the open question.
Adjust the support: Let learners use word help or Level 1 if needed. For a challenge, compare the wording in another level. This activity is not a proficiency test.
Answers to the 3 questions
The question numbers match the student worksheet. Each answer includes a reason and the clue learners can find in the story.
What did the 2023–2025 surveys help researchers estimate?
Correct answer: A — The scale of a gathering already known to scientists
Why: The gathering was already known, and the surveys helped estimate its scale.
Clue in the story: A seasonal aggregation of basketwork eels at Patience Seamount, off Tasmania, could contain up to 2.8 million animals, according to a study led by Australia's CSIRO. Although the gathering was already known, researchers used surveys from 2023 to 2025 to estimate its scale.
Why were underwater images combined with acoustic measurements?
Correct answer: A — Sonar alone could not reliably distinguish the eels from other fish
Why: Sonar alone could not reliably separate eels from other fish, so the team also used images.
Clue in the story: The team combined acoustic measurements with underwater images because sonar alone could not reliably separate the eels from other fish. Evidence from sampled females supports the idea that the animals gather to reproduce, but exactly why they select this seamount remains unresolved.
Which conclusion about reproduction is supported by the article?
Correct answer: A — Samples support the idea that the eels gather to reproduce
Why: Evidence from sampled females supports a reproductive purpose, but the article does not claim every eel was observed reproducing.
Clue in the story: The team combined acoustic measurements with underwater images because sonar alone could not reliably separate the eels from other fish. Evidence from sampled females supports the idea that the animals gather to reproduce, but exactly why they select this seamount remains unresolved.
The open question: accept different answers
Ask learners: Explain why researchers used both acoustic measurements and images, and what remains unresolved.
One possible answer: Sonar alone could not reliably separate eels from other fish, so the researchers also used underwater images. Why the eels choose this seamount is still unresolved.
This is an example, not the only correct answer. Look for a relevant idea, a reason and the learner’s own words. Learners can answer aloud or write one or two sentences.