Dead short-finned eels have been spotted floating beneath the pedestrian bridge at Seaport and lining the riverbanks around Tailrace.

Multiple Launceston residents have taken to social media this month to question the number of dead eels in the waterway.

"Lots of dead eels in the Tamar at Home Point this morning. What's going on?" one said.

Another said: Why do we accept so many dead eels in the Tailrace, and in the upper Tamar. Thousands of eels are killed and left to rot in the Tamar."

The Environment Protection Authority said it had been notified of the problem.

"Between 21 March 2024 and 19 March 2024, the EPA has been notified of three mass eel death events in the Tamar River," an EPA statement read.

"On all occasions it was unlikely that the quantity of eel mortalities caused any significant environmental impacts.

"However localised, temporary odour may have been experienced in some parts of the Tamar River estuary as the eels decomposed."

Dead eels have been left to decompose around the Tamar basin on a number of occasions in recent years.

It is understood the eels are killed in the Trevallyn Power Station intake when they attempt to migrate downstream.

Hydro Tasmania installed an award-winning eel bypass at Trevallyn Dam in mid-2020 to help eels travel downstream safely, however, the problem does not appear to have subsided.

Hydro could not say whether the bypass had resulted in a reduction in eel deaths.

"We don't have historical data on eel deaths," A Hydro Tasmania statement read.

"But we do know that, since the bypass was commissioned in 2020, over 5000 short-finned eels have been able to safely migrate downstream."