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Weird fish makes comeback in Murray River

Donna Coutts, May 3, 2021 6:45PM Kids News

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Lamprey look a bit like eels. Picture: SA Department for Environment and Water media_cameraLamprey look a bit like eels. Picture: SA Department for Environment and Water

environment

Reading level: green

Scientists have found a prehistoric, spooky-looking, bloodsucking, critically endangered native fish in record numbers in the Murray River system.

That’s great news for the health of the environment and for lamprey fish, feared to be almost extinct after the Millennium Drought.

Between July and October last year scientists tracked lamprey. They found 91 pouched lamprey and four short-headed lamprey migrating upstream in the Murray River system from the Coorong in South Australia. It is the most ever recorded in winter.

One fish, which the scientists nicknamed Larry lamprey, was found to have travelled 878km from Goolwa in South Australia to Mildura in Victoria.

Lamprey is an anadromous group of fish species. Anadromous means they need to live in both saltwater and freshwater during an individual’s lifetime. Lamprey fish spawn* in freshwater. Young fish then swim downstream and spend most of their life in the ocean before swimming upstream into freshwater to spawn.

Their jawless mouth with rows of teeth looks and functions a bit like the round attachment that comes with some vacuum cleaners.

A lamprey fish close up. Picture: Department for Environment and Water South Australia media_cameraA lamprey fish with its jawless mouth and rows of teeth. Picture: SA Department for Environment and Water

The Millennium Drought, also called the 2000s drought, lasted from 1996 to about 2009 and is widely regarded as the worst Australian drought since European settlement. The drought meant that for three years there was no water flowing through the lower Murray River system and no connection between the river system and the ocean, so the lampreys couldn’t migrate between freshwater and saltwater.

In recent years there has been more water flowing through the system. In addition, there are now more fishways — a special corridor or staircase to help fish swim upstream — have been installed where the natural flow of a river or creek is interrupted by human-made locks* or weirs*.

Weird fish makes Murray River comeback

Coorong, Lower Lakes and Murray Mouth Program Leader Adrienne Rumbelow said

record numbers of lamprey were tracked migrating from the Southern Ocean to the River Murray in 2020 in search of fresh waters to breed.

“The high numbers of lamprey captured in 2020 highlights the importance of water for the environment in supporting their migration,” she said.

“You need winter flows that are allowed to travel from source to sea, you need fishways at locks and weirs and you need connectivity. If you don’t get these things right you won’t get migration and spawning.

“The fact that we are seeing increasing numbers via our monitoring shows that we have been getting the flow conditions in the river right for these species.

The lampreys were tracked with a type of tag called a PIT tag. These are scanned as the fish move through fishways on upstream weirs on the River Murray.

PIT tag receivers allow the scientists to track the fish as far upstream as Lock 11 at Mildura. A different type of tag, called an acoustic tag, would be needed to learn more about the lampreys’ journey farther upstream from Mildura.

The lamprey project is called Where in the MDB* is Larry?. It’s paid for by the NSW, Victorian, South Australian, and federal governments and co-ordinated by the Murray–Darling Basin Authority.

GLOSSARY

  • spawn: release eggs into the environment, as fish and frogs do
  • locks: short sections of waterways with a gate at each end to control water flow
  • weirs: low walls built across waterways to control water flow
  • MDB: Murray Darling Basin

EXTRA READING

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Very rare walking scorpion fish spotted on Reef

Great news in fight for handfish survival

Murray cod to be trucked to safety

QUICK QUIZ

  1. Who is Adrienne Rumbelow?
  2. How did the scientists know where the fish were going?
  3. When and what was the Millennium Drought?
  4. Who is Larry?
  5. What organisation co-ordinated this project?

LISTEN TO THIS STORY

CLASSROOM ACTIVITIES
1. Ask Larry
Imagine that you could interview Larry lamprey to get more information about this story from his point of view. Write at least three questions that you would ask him. Then, write the answers that you think Larry might give you.

Time: allow 25 minutes to complete this activity
Curriculum Links: English, Geography, Science

2. Extension
Create a cartoon or animation character based on the lamprey fish. Draw your character, give it a name, describe its personality and any special talents, powers or characteristics. Write an outline of a story in which your lamprey is the hero or main character.

Time: allow 40 minutes to complete this activity
Curriculum Links: English, Geography, Science, Visual Arts

VCOP ACTIVITY
Down-Level It
When you up-level a sentence, you do things to it to improve it: make it more interesting, or more complex.

But sometimes, when we read something it can be too complex and we don’t understand it very well. You ask someone to explain it to you, they do (in a simpler way) and you think, well why didn’t they just say that?

Go through the article and find a sentence or two that is complex, or hard to read.

Ask an adult what it means, or try and look some of the words up in the glossary.

Once you know what it means, see if you can rewrite it in a simpler way- down-level it.

Make sure you don’t change the meaning of the sentence in any way though.

Extra Reading in environment