Hydro Tasmania was made aware earlier this month about a number of dead eels washed up on the banks of the Tamar River.

At this time of year the short-finned eels migrate downstream as part of their long journey to the Coral Coast off northern Australia to spawn.

“It’s not unusual for a number of them to go down the power station intake, and this is why we’ve developed a world-first eel bypass system, to help them safely navigate downstream through the dam wall, Hydro Tasmania Environmental Scientist David Ikedife said.

“We are monitoring the system and it is providing a safe alternative route past the power station, which helps to reduce eel mortality.

“However, a dry summer followed by rain recently and increased inflows into Lake Trevallyn has moved more eels than usual into Trevallyn dam and through the power station.”

Mr Ikedife said the eel bypass to enable safe passage of eels downstream had proved successful since its commissioning in 2020, and without it the number of dead eels in the tailrace would have unfortunately been greater.

“We have checked the condition of the eels coming out of the bypass itself and they are healthy,” Mr Ikedife said.

Mr Ikedife said a number of measures were already in place to assist the abundance of the eel population in the South Esk and Tamar River.

“We work with the Inland Fisheries Service (IFS) to catch and transfer juvenile eels upstream to enable them to thrive and grow,” Mr Ikedife said.

“Also in 2006 we built an elver ladder on Trevallyn Dam to help juvenile eels traverse up the South Esk River. This has resulted in hundreds of thousands of juvenile eels migrating upstream each year.

“And we have planning in place to increase monitoring of the downstream migration of the eels.

“But it is also important to understand that a closely related species of freshwater eels from the northern hemisphere, when spawning, release millions of eggs per female.

“We are also in the planning phase of tracking how many eels use the bypass and how many traverse the power station to further assess its effectiveness.”

ENDS