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Where in the MDB is Larry the Lamprey?

Lamprey are an ancient, eel-like fish that can migrate from the ocean up to 2000 km along the River Murray to breed.

In 2020, researchers tracked lamprey movements up the River Murray to learn more about their movement and solve the mystery of where they spawn, as well as help inform how the river is managed to better support these fish. Lampreys were tagged with passive integrated transponder (PIT) tags which are then scanned as they move through River Murray fishways.

Record numbers of lamprey made the journey up the river and you can see how far they went in this video:

Lamprey monitoring is funded by The Living Murray, a joint initiative funded by the New South Wales, Victorian, South Australian, and Commonwealth governments and coordinated by the Murray–Darling Basin Authority.

Here’s a summary of Larry’s adventures in 2020:

  • 91 pouched lamprey and four short-headed lamprey were trapped and tagged (implanted with PIT tags) at the Lower Murray barrages near Goolwa.
  • 21 per cent of tagged pouched lamprey and 25 per cent of tagged short-headed lamprey reached at least Lock 1 at Blanchetown.
  • The longest recorded distance travelled by a pouched lamprey was to Lock 11 (more than 878 km), and for a short-headed lamprey to Lock 2 (more than 362 km).
  • September 2020 was the busiest month for lamprey migration with the most fishway detections.
  • The fastest lamprey was clocked travelling between Locks 3 and 4 with an average speed of approximately 55 km a day (and as they only travel at night time, this equates to four and a half kilometres an hour!).
  • The slowest lamprey was clocked at only seven km a day, between the barrages and Lock 1.

Lamprey fast facts

  • Lamprey are an ancient, eel-like fish that have been around for about 360 million years.
  • Born in fresh water, they move to the sea as young adults where they spend much of their life before returning to fresh water to breed, lay eggs and then die.
  • In the ocean, lamprey feed parasitically on host fish or whales whereby they attach their suction-like mouths onto the side of their host, use their tongue to scrape away scales and skin and suck the host’s blood.
  • When lamprey start their spawning migration up the River Murray they change their internal organs, investing in their reproduction system rather than digestive system and in doing so, stop feeding.
  • To kick start their migration up the River Murray, lamprey at sea need a freshwater signal.  Freshwater flows carry the smell of pheromones to help them identify productive breeding habitat and coordinate breeding behaviour.
  • Lamprey can migrate thousands of kilometres to breed, which is why it’s really important that the entire river is connected through things like fishways at locks and weirs.
  • Even though lamprey have been around for millions of years, and are native to the River Murray, we’re still not sure where they breed in the Murray-Darling Basin.
  • While they may look scary they are not dangerous to people or animals in the River Murray, they only have one thing on their mind once they start their journey up river and it’s not food!
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