News by Levels · Level 3 · Student worksheet
Sonar and Cameras Reveal Scale of Deep-Sea Eel Gathering
Name: __________________________ Date: __________________
Read 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.
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.
Source: ABC News Australia, 2026-10-28. https://www.abc.net.au/news/science/2026-10-28/australia-biggest-eel-ball-2-8-million-off-tasmania/107309716
Read and practise
What did the 2023–2025 surveys help researchers estimate?
- The scale of a gathering already known to scientists
- The age of the underwater mountain
- The location of a previously unknown gathering
Why were underwater images combined with acoustic measurements?
- Sonar alone could not reliably distinguish the eels from other fish
- Sonar alone showed where all the eels reproduced
- Camera images could identify individual eels for a complete count
Which conclusion about reproduction is supported by the article?
- Samples support the idea that the eels gather to reproduce
- Researchers directly observed every eel reproducing
- Samples establish that the gathering is mainly for feeding
Your turn
Explain why researchers used both acoustic measurements and images, and what remains unresolved.
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Read online: https://newsbylevels.com/news/tasmania-eels-patience-seamount-estimate-october-2026/level-3/