Species considered extinct found alive and well at yingina

29 April 2022

Accidental discoveries are a foundation of science. And Hydro Tasmania can now add a very tiny one to the list – tiny in size but not importance!

It’s a curious tale of roof tiles, limpets, a massive lake, a dedicated field ecologist and water quality consultant at our engineering arm, Entura, and one very tiny snail.

The team was initially searching at yingina / Great Lake for another previously thought to be extinct snail species, the Great Lake giant freshwater limpet (Ancylastrum cumingianus). It was rediscovered during an aquatic invertebrate survey when the lake was at a historic low.

As part of Hydro Tasmania’s environmental surveys, the team returned to the now refilled lake late last year, armed with old roof tiles sourced from a tip shop, plus ropes and buoys.

Entura’s Field Ecologist and Water Quality Consultant Kevin Macfarlane explains that the tiles were lowered to various depths (2-10 metres) to the lake floor in the hope they would become inhabited by bottom-dwelling species, such as the limpet.

Returning in January this year to retrieve the tiles, Kevin said that they not only found the limpets but also three very tiny specimens of an aquatic snail called Beddomeia tumida – the first time the live snail has been recorded in the area since 1900.

Beddomeia tumida is only known to inhabit yingina / Great Lake. It is listed as endangered on the Tasmanian Threatened Species Protection Act 1995 (TSPA), and critically endangered but possibly extinct on the IUCN red list.

“This species of freshwater snail was thought likely to be extinct. But subsequent surveys have recorded further specimens of both snails on other tiles, so far in relatively low numbers,” he said.

The 4mm snail species was identified with the help of Dr Karen Richards, senior zoologist and aquatic mollusc expert at the Threatened Species Section, Department of Natural Resources and Environment Tasmania.

“It’s a significant find because we now know it still exists. Once we get an idea of population size, it could potentially have its listing changed to be no longer critically endangered, and hopefully we find that it’s abundant,” Kevin said.

yingina / Great Lake was the first source of water for Hydro Tasmania. It initially fed Waddamana Power Station, which was run by the Tasmanian Government-owned Hydroelectric Department from 1916 until 1964, and replaced by Poatina Power Station in 1966.

Kevin explained that the ongoing conservation monitoring helped Hydro Tasmania to understand the health of the lake.

“Our ongoing monitoring confirms the lake water is of good quality and the lake itself appears to have resilient inhabitants. We’ve discovered not only undescribed freshwater snails in Great Lake, but numerous small crustaceans, and an aquatic plant called a charophyte. We’ve also uncovered previously unknown sponges in some of the other Central Highlands Lakes and found animals in other lakes where they weren’t known to exist.”

“The more knowledge we gain on the flora and fauna of the lake, the greater chance we have to protect them.”



Released for Hydro Tasmania by Lyn Southon / 0409 722 359 / media@hydro.com.au


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