NewsBite

Energy minister Guy Barnett and Hydro Tasmania aquatic scientist David Ikedife at Trevallyn Dam. Picture: PATRICK GEE
Energy minister Guy Barnett and Hydro Tasmania aquatic scientist David Ikedife at Trevallyn Dam. Picture: PATRICK GEE

Epic eel migration gets leg up through Australian first infrastructure project

THE incredible migration of the slippery short-finned eel from Launceston to New Caledonia has become a lot easier since the installation of a bypass through the wall of Trevallyn Dam.

Tuesday was World Nature Conservation Day and Hydro Tasmania announced the completion of the $1m project to help protect the native species and relieve stress on its breeding cycle.

Tiny larval eel babies – known as glass eels because of their transparency – drift down to New Zealand, Tasmania and other parts of Australia on currents from the Coral Sea.

When they sense freshwater, they swim upstream, metamorphose, attain the typical eel shape and colour and become juvenile ‘elvers’.

Water flowing through a bypass in the Trevallyn Dam wall for migrating short-finned eels. Picture: Supplied/Hydro Tasmania
Water flowing through a bypass in the Trevallyn Dam wall for migrating short-finned eels. Picture: Supplied/Hydro Tasmania

They live in dams and streams for 10-35 years until they mature, before making the almost 3000km journey out to sea and north to spawn before they die.

An eel ladder was installed at the Trevallyn Dam in the 1990s so juvenile eels could get upstream.

But, until now, the eels have relied on either the dam spilling or have tried to pass through the Trevallyn Power Station intake to get back down stream for their migration.

The former is uncommon and the latter can be fatal for the eels.

Hydro Tasmania aquatic scientist David Ikedife said this was the first time any dam in Australia had been fitted with an eel bypass for downstream migration.

The organisation tagged and tracked the movements of eels looking for a way downstream before drilling a hole in the dam wall in a corner regularly explored by the eels and installing a chute.

“A lot of research and development has gone in to this, and population numbers will be carefully monitored to see what effect it has,” Mr Ikedife said.

Juvenile short-finned eels. Picture: Supplied/Hydro Tasmania
Juvenile short-finned eels. Picture: Supplied/Hydro Tasmania

“During the eel’s downstream migration from December to April each year, visitors to Trevallyn Dam will see the small cascade of water from the eel bypass in operation and will know Hydro Tasmania is helping this native species on its long journey.”

Hydro Tasmania CEO Steve Davy said part of the organisation’s duty to look after the waterways in its care, including the species which inhabit them.

“Though not endangered in Australia, similar species of eels are listed as threatened in the Northern Hemisphere, so the responsibility is on water managers like Hydro Tasmania to take action,” Mr Davy said.

Energy minister Guy Barnett said Hydro Tasmania should be congratulated for assisting the migration of the eels and helping to maintain the biodiversity the river system.

“It’s an Australian first, it’s a million dollar investment and on Nature Conservation Day, it’s a great initiative to announce,” he said.

patrick.gee@news.com.au

Add your comment to this story

To join the conversation, please Don't have an account? Register

Join the conversation, you are commenting as Logout

Original URL: https://www.themercury.com.au/news/tasmania/in-depth/epic-eel-migration-gets-leg-up-through-australian-first-infrastructure-project/news-story/b51c4a0e4837932b6dd91f05d045e69a